Buddha's hand

Buddha's Hand (Citrus medica var. sarcodactylis): A Comprehensive Reference

Identity and Botanical Description

Taxonomic and Chemical Names

Citrus medica L. var. sarcodactylis (Noot.) Swingle, commonly known as Buddha's hand or fingered citron, is a variation of Citrus medica L. and belongs to the genus Citrus, family Rutaceae. In Traditional Chinese Medicine (TCM), the dried fruit is known by its pharmaceutical name Fructus Citri Sarcodactylis, or more commonly as Fo Shou (佛手), meaning "Buddha's hand" in Chinese. Common synonyms and names include Buddha's Hand, Fingered Citron, Bushukan (Japanese), Fo Shou (Chinese), and Citrus sarcodactylis.

The specific epithet medica means "medicinal," while the variety name sarcodactylis derives from the Greek words sarkos, meaning "fleshy," and dactylos, meaning "finger," in obvious reference to the fruit's appearance.

Plant Morphology

Buddha's hand, or fingered citron, is a thorny shrub or small tree that typically matures to 8–15 feet tall. Like other citron varieties, it has long, irregular branches covered in thorns. Its large, oblong leaves are pale green and grow about four to six inches. Its white flowers are tinted purplish from the outside and grow in fragrant clusters.

The fruit is segmented into finger-like sections, resembling those seen on representations of the Buddha. The unique fruit, which can grow to 6–10 inches long, separates as it ripens into finger-like projections that have an inner white pith but no juice or pulp. The different cultivars and variations form a gradient from "open-hand" types with outward-splayed segments to "closed-hand" types, in which the fingers are kept together. There are also half-fingered fruits, in which the basal side is united and the apical side fingered.

Origin and Cultivation

The origin of this kind of citron is commonly traced back to South or East Asia, probably northeastern India or China, where most domesticated citrus fruits originate. Fingered citron is native to Southeast Asia, including northeastern India, Myanmar, and southern China, with notable cultivation in provinces such as Guangdong and Yunnan. The main producing areas are in the south of China, especially in Guangdong, Fujian, Sichuan, and Zhejiang provinces.

It is relatively new to places like the United States, having first been introduced in the late 1800s, with commercial growing not beginning until the 1980s.

Common Forms and Preparations

Buddha's hand is used in a variety of forms across culinary, medicinal, and ornamental contexts:

• Dried fruit slices: The sliced, dried peel of immature fruits is prescribed as a tonic in traditional medicine.
• Decoctions and teas: In TCM, dried Buddha's hand is called Fo Shou. Fo Shou tea and tinctures are the typical forms used.
• Essential oil: The essential oil from Buddha's hand is extracted through cold pressing the peel; steam distillation has been used for extracting oil from the leaves of the fruit.
• Polysaccharide extracts: Various extraction methods such as solvent extraction, ultrasound-assisted, and microwave-assisted extraction have been used to obtain fingered citron polysaccharides (FCPs).
• Preserved and candied fruit: As a food, finger citron is commercially processed into preserved fruit and health tea drinks.
• Whole fresh fruit: Used for its intense fragrance for room scenting, religious offerings, and culinary zesting of the rind.

Traditional and Historical Use

China: The Primary Traditional Context

Fo Shou has a long history in China, with its ancestor plant, the citron (Gou Yuan / Xiang Yuan), first recorded in the Eastern Han dynasty text Yi Wu Zhi (《异物志》) by Yang Fu. The name appeared as "Gou Yuan" (枸橼) through the Jin and Tang dynasties, including in Chen Cangqi's Tang dynasty Ben Cao Shi Yi (《本草拾遗》). By the Yuan dynasty, it was commonly called "Xiang Yuan" (香橼). The distinct finger-fruited variety we now call Fo Shou was formally described in Li Shizhen's Ben Cao Gang Mu (Ming dynasty), where it was named "Xiang Yuan" and "Fo Shou Gan." The earliest dedicated medicinal record of Fo Shou as such is attributed to Lan Mao's Dian Nan Ben Cao (《滇南本草》, Ming dynasty).

Buddha's hand was important by the 10th century A.D. in Fujian. Chinese artists classically depicted the fruit in jade and ivory carvings, in prints, and on lacquered wood panels.

Practitioners of Traditional Chinese Medicine (TCM) utilized Buddha's hand (known as "fo shou") to harmonize the body's vital energy, or qi. It is especially renowned for its ability to soothe the liver, alleviate pain, and regulate digestion. Common remedies included using dried Buddha's Hand peel to treat coughs, chest congestion, and digestive discomforts such as bloating and poor appetite.

In TCM classification, finger citron is considered mild, with a pungent and bitter taste and aromatic fragrance, and belongs to the liver, spleen, stomach, and lung tropism. It contains essential oil, flavonoids, polysaccharides, amino acids, coumarins, polyphenols, proteins, vitamins, and other physiologically active substances. Finger citron soothes the liver and regulates qi, harmonizes the stomach and arrests pain, dries dampness and resolves phlegm, and treats costal pain, chest tightness, liver and stomach disharmony, and spleen and stomach stagnation caused by liver qi depression.

Religious and Symbolic Use

Buddha's hand fruit is very fragrant and is used predominantly in China and Japan for perfuming rooms and personal items such as clothing. The fruit may be given as a religious offering in Buddhist temples. According to tradition, Buddha prefers the "fingers" of the fruit to be in a position where they resemble a closed rather than open hand, as closed hands symbolize the act of prayer. In China, the Buddha's hand is used as a symbol of happiness, longevity, and good fortune. It is also a traditional temple offering and a New Year's gift.

In China, the Buddha's Hand citron symbolizes happiness and long life, because its name, "fo-shou," has those meanings when written with other characters. Chinese like to carry the fruit in their hands, place it on tables in their homes, and present it as a sacrificial offering at temple altars.

Japan

In Japan, the "bushukan," as the Buddha's Hand citron is called, is a popular gift at New Year's, as it is believed to bestow good fortune on a household. It is also used by Japanese for perfuming rooms and clothing.

Taiwan and Broader Folk Medicine

In eastern countries where it is known as fingered citron or Fo Shou, the fruit is traditionally used in folk medicine. In China, Buddha's hand is appreciated as a tonic, antispasmodic, antiemetic, and expectorant, while in Taiwan it is used for the treatment of stomachache, headache, edema, rheumatism, infectious hepatitis, and arthritis. It is also taken as an adjuvant in the treatment of respiratory tract infections, asthma, and hypertension.

Key Constituents and Active Compounds

Phytochemical Overview

Fingered citron is abundant in multiple bioactive constituents, including limonoids, flavonoids, essential oils, polyphenols, terpenes, and polysaccharides. The bioactive compounds present in fingered citron synergistically contribute to its health benefits and therapeutic effects, positioning it as a valuable ingredient in herbal remedies and tonics.

A comprehensive phytochemical review published in PMC identifies the following specialized metabolites across the Citrus medica species: flavonoids (apigenin, hesperetin, hesperidin, naringin, naringenin, rutin, quercetin, and diosmin), coumarins (citropten, scoparone, and bergapten), terpenes (limonene, γ-terpinene, limonin, and nomilin), and phenolic acids (p-coumaric acid, trans-ferulic acid, and chlorogenic acid).

Essential Oil Composition

A 2022 study published in Molecules (PMC8911557) found that the volatile profile of the essential oil (EO) extracted from Buddha's hand exocarp was characterized by limonene (66.9%) and γ-terpinene (20.0%) as the most abundant compounds, while α-terpineol (44.7%) and terpinen-4-ol (21.6%) were the predominant constituents in the hydrolate. Several minor monoterpene components, such as α-thujene, α-pinene, β-myrcene, β-pinene, and geranyl acetate, were also identified in the essential oil. The extracts were also rich in furan and coumarin derivatives.

In a metabolite profiling study, a total of 62 volatiles were identified across flower, leaf, and fruit, with limonene and γ-terpinene being the most abundant. Studies have confirmed quantitative differences with regard to the major constituents — limonene, γ-terpinene, geranial, and neral — and several chemical compositions of the same variety have been reported according to geographical origins.

Polysaccharides

Fingered citron polysaccharides (FCPs) typically contain polysaccharides such as pectin, hemicellulose, arabinogalactan, xylan, and cellulose — complex carbohydrate compounds derived from the fingered citron fruit. FCPs are considered key bioactive components of Citrus medica L. var. sarcodactylis, garnering global attention for their potential medicinal and culinary benefits.

A 2022 study in PMC (PMC9225144) isolated a specific polysaccharide from fingered citron: A new polysaccharide named K-CMLP was isolated and purified with an average molecular weight of 3.76 × 10³ kDa. Monosaccharide composition analysis revealed that K-CMLP consisted of rhamnose, galactose, and glucose, with a molar ratio of 6.75:5.87:1.00.

Flavonoids

The fruit has been found to contain abundant flavonoids — including neohesperidin, hesperetin, and tangeretin — as well as coumarins including xanthotoxol, byakangelicin, and bergapten, and organic acids including malic acid, 5-hydroxyferulic acid, and citric acid.

Coumarins

Bioassay-guided investigation of Citrus medica L. var. sarcodactylis stem and root barks led to the isolation of a new coumarin, citrumedin-B, and thirty known compounds. The anti-inflammatory components were found to be xanthyletin, nordentatin, atalantoflavone, and lonchocarpol A, which displayed potent nitric oxide (NO)-reducing activity in microglial cells.

Other Bioactive Compounds

Consumer demand for natural active substances has driven growing attention toward finger citron's bioactive components, including essential oils, coumarins, flavonoids, amino acids, minerals, and polysaccharides. The fruit also contains amino acids, proteins, vitamins, and physiologically active aldehydes such as (Z)-3,7-dimethylocta-2,6-dienal.

Mechanisms of Action

Anti-Inflammatory Pathways

Research has demonstrated an anti-inflammatory effect of the essential oil and its constituents from fingered citron through blocking JNK, ERK, and NF-κB signaling pathways in LPS-activated RAW 264.7 cells. This in vitro work, published in Food Chemistry and Toxicology (2013), provides a mechanistic basis for traditional anti-inflammatory applications.

One PMC polysaccharide study investigated K-CMLP as an antioxidant against DPPH and ABTS radicals and examined anti-inflammatory activities including effects on the production of pro-inflammatory cytokines (TNF-α and IL-6), as well as cell count and reactive oxygen species (ROS) scavenging activity in LPS-induced RAW 264.7 cells.

Modern pharmacological studies have shown that bergapten and flavonoids in finger citron fruit can reduce the release of pro-inflammatory factors, thereby protecting lung tissue.

Antioxidant Mechanisms

The sarcodactylis variety showed the highest antioxidant activities (77.2%) in a DPPH assay. Overall, antioxidant bioactive compounds are often confirmed by in vitro assays; however, they are characterized by poor absorption through biological barriers.

Immunomodulatory Mechanisms

FCPs have attracted interest because of their potential health benefits and bioactivities, including antioxidant activity, immunomodulatory effect, anti-inflammatory properties, anti-cancer potential, hypoglycemic effect, and gastroprotective effect.

Gastroprotective Pathways

Docking experiments have revealed strong binding affinity interactions of compounds in Citrus medica var. sarcodactylis with TLR-4, the Nrf2-Keap1 complex, and pNF-κBp65. The mechanism of action of the extract exerting an anti-ulcer effect was postulated to be based on the synergistic action of compounds possessing anti-inflammatory, antioxidant, and anti-apoptotic activities.

Scientific Evidence by Area of Use

Note: The vast majority of available evidence for Buddha's hand is preclinical — derived from in vitro cell culture experiments and in vivo animal models. Human clinical trials are extremely limited. This distinction is maintained throughout the following sections.

Inflammation and Immune Modulation

In vitro and animal evidence: Research has documented anti-inflammatory, immunoregulatory, antibiofilm and antibacterial, antiviral, hepatoprotective, neuroprotective, hypolipidemic, and antioxidant properties of Citrus medica var. sarcodactylis.

A 2013 study published in Food Chemistry and Toxicology (cited in PMC10500571) demonstrated the essential oil's inhibition of NF-κB and MAPK (JNK, ERK) signaling in macrophage cell lines — pathways central to inflammatory cytokine release. Anti-inflammatory, antimicrobial, antioxidant, cytotoxic, and hypoglycemic effects of Buddha's hand extracts or essential oils obtained from different parts of the plant (fruits, leaves, peels, roots, stems) have been reported.

A 2022 PMC study (PMC9225144) on the galactorhamnan polysaccharide K-CMLP found suppression of TNF-α and IL-6 production in LPS-stimulated macrophages. This is cell-based evidence only.

A 2025 PMC study (PMC12400161) examined Citri Sarcodactylis Fructus (CSF) in an LPS-induced acute lung injury (ALI) model: Its traditional use in treating respiratory diseases provides a theoretical basis for the treatment of ALI, and modern pharmacological studies have shown that bergapten and flavonoids in CSF can reduce the release of pro-inflammatory factors to protect lung tissue. This study was conducted in animals and cell models, not in humans.

Evidence strength: Preliminary; in vitro and animal data only. No human clinical trials on inflammation endpoints have been identified.

Gastrointestinal Health

Traditional context: As a folk medicine, finger citron has been traditionally utilized for the treatment of chronic diseases such as stomach ache, edema, headache, rheumatism, arthritis, tracheitis, asthma, respiratory infections, and hypertension.

Animal evidence: A study published in the Journal of Drug Delivery Science and Technology (2024, ScienceDirect) tested a methanol extract of Citrus medica var. sarcodactylis in a rat gastric ulcer model. The extract and its nano-formulation were given to rats at a dose of 600 mg/kg/day for one week, along with a single oral administration of ethanol (5 ml/kg) on day 7. Nano-CMF showed superior potent anti-ulcer activity compared to CMF and the conventional therapy omeprazole. This is an animal study and results cannot be directly extrapolated to humans.

Limited human evidence: Globus pharyngis is the medical term for the constant feeling of having a lump in the throat. At Yangzhou University in China, 46 patients were treated with the TCM remedy Fo Shou made from the fruit. The dosage was taken 3 times per day and was found to be more effective at alleviating this side effect versus the sore-throat treatment it was compared against. This is a single small clinical study; no details on study design, blinding, or statistical rigor are available in accessible sources, and it cannot be considered high-quality clinical evidence.

Evidence strength: Traditional use is well-documented. Animal models show gastroprotective activity. Human evidence is limited to a single small study with inadequate reporting of methodology.

Antioxidant Activity

In vitro evidence: Particular scientific attention has been focused on the antioxidant, anti-inflammatory, antimicrobial, antidiabetic, anticancer, and neuroprotective activity of Citrus medica. The 2022 Molecules study (PMC8911557) chemically characterized the essential oil and methanol extracts of Buddha's hand fruit and evaluated their antiradical and cytotoxic properties using standardized DPPH and ABTS assays. Limonene and γ-terpinene were found to be the most abundant compounds both in the fresh parts of the fruit and in the essential oil.

Evidence strength: Antioxidant activity is well-demonstrated in vitro. Whether this translates to meaningful in vivo antioxidant effects in humans has not been tested in clinical trials. Antioxidant bioactive compounds are characterized by poor absorption through biological barriers.

Antimicrobial Activity

In vitro evidence: Finger citron essential oils have demonstrated antioxidant, antibacterial, and antibiofilm activities in laboratory studies. The 2022 Molecules study (PMC8911557) evaluated antibacterial activity of the essential oil and extracts against standard bacterial strains using in vitro assays.

Evidence strength: In vitro data only. No human trials have evaluated clinical antimicrobial efficacy.

Metabolic Effects (Hypoglycemic and Hypolipidemic)

Animal evidence: Researchers have reported that the essential oils in Buddha's hand appeared to have beneficial effects on blood glucose levels in rats. This was a preclinical study only.

FCPs have demonstrated a hypoglycemic effect in research models. The review of FCPs (ScienceDirect, 2024) notes these effects but contextualizes them entirely within in vitro and animal experiments.

Evidence strength: Preliminary; animal and cell-based data only. No human clinical trials on glucose or lipid endpoints are reported in identified sources.

Neuroprotective and Neurotrophic Activity

In vitro evidence: Scientists in Taiwan found that when cultured cells were exposed to a water-based Buddha's hand extract, there was higher expression of fibroblast growth factor (FGF-2), which promoted the growth of Schwann cells that make the sheath surrounding neuronal axons. The more extract was used, the higher the FGF-2 production observed. This in vitro study (published in the American Journal of Chinese Medicine, 2014) cannot be interpreted as clinical evidence of neuroprotection in humans.

Evidence strength: Single in vitro study; not replicated in animals or humans to date in published sources found.

Cytotoxic and Anticancer Activity

In vitro evidence: An exocarp ethanol extract from C. medica var. sarcodactylis was more cytotoxic (EC50 1.76 mg/mL) than a mesocarp extract (EC50 not attained) in an HL60 leukemia cell line. This might be explained by the strong presence of coumarins, which have been reported to have good anticancer activity.

Evidence strength: In vitro cell line data only. No animal tumor models or human oncology trials for Buddha's hand specifically have been identified in authoritative sources.

Body Systems and Health Areas

Based on the totality of traditional use and preclinical research, Buddha's hand is associated with the following body systems:

• Gastrointestinal/Digestive System: Traditionally indicated for costal pain, chest tightness, liver and stomach disharmony, and spleen and stomach stagnation.
• Respiratory System: In China, used as an antispasmodic and expectorant; in Taiwan, as an adjuvant in the treatment of respiratory tract infections and asthma.
• Hepatic (Liver) System: In TCM, the fruit belongs to the liver tropism; preclinical studies have noted hepatoprotective properties.
• Immune System: FCPs have demonstrated immunomodulatory effects in laboratory research.
• Nervous System: In vitro data suggest potential neurotrophic activity via FGF-2 pathway activation in Schwann cells.
• Cardiovascular/Metabolic System: Traditional use for hypertension has been recorded. Preclinical evidence suggests hypolipidemic and hypoglycemic effects.

Dosage Forms and Reported Dosages

The following dosages are reported strictly as stated in identified sources and reflect traditional TCM practice or experimental parameters — not recommended clinical doses.

Traditional Chinese Medicine Dosages

Lower doses (3 to 6 g) are suitable for mild Qi stagnation with bloating and poor appetite. Higher doses (6 to 9 g) are used for more pronounced liver-stomach Qi stagnation with chest and flank distension or epigastric pain. For phlegm-dampness cough, the standard dose is combined with phlegm-resolving herbs.

Doses up to 15 g in standard decoction are described for stronger Qi-moving effect. Historical pediatric hepatitis protocols used up to 30 g of aged Fo Shou daily in older children (ages 7 to 10), combined with other herbs under practitioner supervision.

Fresh Fo Shou can also be used (12 to 15 g) when available, brewed as tea for milder effect. Aged Fo Shou (Chen Fo Shou) is traditionally preferred for treating dysentery with tenesmus.

Experimental / Preclinical Dosages

In a rat gastric ulcer model, fruit extract was administered at a dose of 600 mg/kg/day for one week.

Safety Considerations

General Toxicity Profile

FCPs are natural compounds extracted from the fingered citron plant that have garnered substantial attention regarding their safety profile. Extensive research has been conducted to evaluate the toxicity of FCPs, with studies consistently indicating their low toxicity at appropriate doses. In vivo experiments demonstrated no significant adverse effects on major organs or physiological functions, corroborated by in vitro cell culture studies.

Traditional Cautions

Excessive long-term use in people without true Qi stagnation may scatter Qi, leading to fatigue or weakness. This reflects a TCM-specific contraindication based on constitutional assessment rather than pharmacological mechanism.

Furocoumarin-Related Phototoxicity (Essential Oil / Topical Use)

Buddha's hand fruit contains the coumarin bergapten (also known as 5-methoxypsoralen, or 5-MOP), a compound identified in the fruit's constituent analysis. Bergapten (aka 5-methoxypsoralen or 5-MOP) is a naturally-occurring phototoxic furanocoumarin (psoralen) in citrus peel oils. Furocoumarins are a class of naturally occurring organic compounds including substances like psoralen, methoxsalen, bergapten, and oxypeucedanin. Many furocoumarins are phototoxic and can cause phytophotodermatitis upon exposure to UV light. They are common in the Rutaceae plant family, which includes citrus fruits.

Citrus peel oils containing components such as bergapten, citropten, bergamotene, and other furocoumarins may cause phototoxic effects when applied to sun-exposed skin. Psoralen can induce skin cancer due to the formation of covalent DNA adducts upon exposure to ultraviolet A or solar light.

The International Fragrance Association (IFRA) has issued specific limits for furocoumarin-containing essential oils applied to skin: Finished products that are applied to the skin, excluding rinse-off products, must not contain more than 0.0015% or 15 ppm 5-MOP. This equates to a level of 0.0075% or 75 ppm in a fragrance compound when used at 20% in a consumer product applied to the skin.

The photosensitivity risk primarily applies to cold-pressed essential oils used topically: Furocoumarins are relatively non-volatile molecules and are generally found in expressed (cold-pressed) citrus fruit oils, but not in distilled citrus fruit oils.

Citrus Allergy

In a retrospective study (2001–2010) of professional food handlers in Denmark, 8.5% (16/188) of patients had positive skin prick test reactions to orange peel and 7.9% (15/191) had positive reactions to lemon peel. While this data pertains to related citrus species rather than Buddha's hand specifically, the shared botanical family and similar constituent profile make cross-reactivity plausible, though this has not been specifically studied for Citrus medica var. sarcodactylis.

Limitations of the Evidence Base

Clinical studies in humans are limited. Most evidence is preclinical, and rigorous clinical trials are needed to substantiate specific health claims and establish safe dosages. In recent years, scientific attention has focused on the antioxidant, anti-inflammatory, antimicrobial, antidiabetic, anticancer, and neuroprotective activity of Citrus medica — but the translation of these findings into clinically validated applications for Buddha's hand specifically remains incomplete.

References

• PMC9225144 — Structural Characterization and Anti-inflammatory Activity of a Galactorhamnan Polysaccharide From Citrus medica L. var. sarcodactylis (PMC / Frontiers in Nutrition, 2022)
• PMC8911557 — Detection of Volatiles by HS-SPME-GC/MS and Biological Effect Evaluation of Buddha's Hand Fruit (Molecules, 2022)
• PMC6151612 — Constituents of the Fruits of Citrus medica L. var. sarcodactylis and the Effect of 6,7-Dimethoxy-coumarin on Superoxide Anion Formation and Elastase Release (Molecules, 2017)
• PMC10301705 — An Insight into Citrus medica Linn.: A Systematic Review on Phytochemical Profile and Biological Activities (PMC, 2023)
• PMC10500571 — Evaluation of the Antioxidant Potential of Citrus medica from Different Geographical Regions and Characterization of Phenolic Constituents by LC–MS (PMC, 2023)
• PMC5079152 — Volatile and Flavonoid Composition of the Peel of Citrus medica L. var. Corsican Fruit for Quality Assessment of Its Liqueur (PMC, 2016)
• PMC12400161 — Citri Sarcodactylis Fructus Alleviates LPS-Induced Acute Lung Injury by Inhibiting Inflammation and Inflammasome Activation (PMC, 2025)
• PubMed 20045968 — Anti-inflammatory principles from the stem and root barks of Citrus medica (Chemical & Pharmaceutical Bulletin, 2010)
• ScienceDirect — Review of polysaccharides from Citrus medica L. var. sarcodactylis: extraction, purification, structural characteristics, bioactivity and potential applications (2024)
• ScienceDirect — Anti-ulcerogenic activity of Citrus medica var. sarcodactylis fruit extract nano-emulsion in gastric ulcer rat model (2024)
• ScienceDirect — Variation in Chongqing finger citron components and antioxidant activity from essential oils in several organs (2024)
• ScienceDirect — Structural characterization and immunomodulatory activity of a polysaccharide from finger citron extracted by continuous phase-transition extraction (2023)
• PMC6680504 — Integration of Metabolite Profiling and Transcriptome Analysis Reveals Genes Related to Volatile Terpenoid Metabolism in Finger Citron (C. medica var. sarcodactylis)
• Wikipedia — Buddha's hand (botanical and cultural overview)
• Givaudan Citrus Variety Collection at UC Riverside — Buddha's Hand citron (horticultural and historical description)
• Missouri Botanical Garden Plant Finder — Citrus medica var. sarcodactylis
• Me & Qi Herb Database — Fo Shou (Finger Citron Fruit): TCM Herb
• Cosmetic Ingredient Review (CIR) — Safety Assessment of Citrus-Derived Peel Oils as Used in Cosmetics (2014)
• PMC4345801 — Citrus bergamia essential oil: from basic research to clinical application (phototoxicity and furocoumarin context)