Coca (Erythroxylum coca)
1. Identity and Botanical Description
Taxonomy and Botanical Names
Coca refers primarily to the leaves and whole-plant preparations derived from species within the genus Erythroxylum, family Erythroxylaceae. The genus Erythroxylum contains species used by indigenous people of South America long before the domestication of plants; two species, E. coca and E. novogranatense, have been utilized for thousands of years specifically for their tropane alkaloid content. The accepted full scientific designation for the principal cultivated form is Erythroxylum coca Lam. (Lamarck, 1786). Under the 1961 United Nations Single Convention on Narcotic Drugs, "coca leaf" is defined as the leaf of the coca bush — with "coca bush" referring to any plant of any species of the genus Erythroxylum.
Cultivated Varieties
Four principal cultivated taxa are recognized:
- Erythroxylum coca var. coca — found in wet montane forests of the eastern Andean slopes of Peru and Bolivia.
- Erythroxylum coca var. ipadu — grown in the lowland Amazon basin.
- Erythroxylum novogranatense var. truxillense (Trujillo coca) — grown primarily in the Cajamarca and Amazonas regions of Peru.
- Erythroxylum novogranatense var. novogranatense (Colombian coca), distributed in the drier inter-Andean valleys and coastal lowlands of Colombia.
All four of the cultivated cocas were domesticated from Erythroxylum gracilipes in pre-Columbian times, with significant archaeological sites reaching from Colombia to northern Chile.
Plant Morphology
Coca is a shrub to about 2 m high, native to Peru, Bolivia, and Colombia, and now widely introduced to tropical countries. Typical characteristics of the family are elliptic, light green leaves (4–7 × 3–4 cm), small white flowers, and small reddish-orange drupes. Dried leaves are uncurled, deep green on the upper surface, grey-green on the lower, and have a strong tea-like odour. A distinctive botanical feature of coca leaves is the presence of an areolate portion bounded by two longitudinal curved lines on each side of the midrib, visible particularly on the underside of the leaf.
Common Names and Preparations
Common English names include "coca," "cocaine plant," and "coca leaf." Coca leaves are used commercially and industrially in teas, foods, cosmetics, and beverages. The major preparations include:
- Leaf chewing (acullico / acullicado): The most common method consists of forming a small bolus with selected leaves and placing it between the cheek and the gum. An alkaline mixture called llipta activates the release of active ingredients through a chemical reaction; the bolus can remain in the mouth for hours, releasing its properties slowly and sustainedly.
- Coca tea (mate de coca): Consumed in the form of an infusion, very popular in Peru, Bolivia, and Ecuador.
- Coca flour and food products: Coca leaf flour (finely ground coca leaves) can be used to make a strong tea and is sold as a nutritional supplement.
2. Traditional and Historical Use
Prehistoric Origins
Called the "Divine Leaf" by the Inka, coca has been cultivated for over 8,000 years and is the most culturally significant pharmaceutical plant in South America. Chewing coca in South America began by at least 8,000 cal BP: leaf fragments of that date were found in house floors in the Nanchoc Valley, Peru. These deposits included pieces of calcite — the alkaline mineral used by chewers to facilitate alkaloid release — confirming the practice was already established during the Early Holocene. Beginning with the Valdivian culture, c. 3000 BC, there is an unbroken record of coca leaf consumption by succeeding cultural groups on the coast of Ecuador until European arrival, as shown in their ceramic sculpture and abundant lime pots (caleros). Extensive archaeological evidence for the chewing of coca leaves dates back at least to the 6th century AD Moche period, and the subsequent Inca period, based on mummies found with a supply of coca leaves and pottery depicting the characteristic cheek bulge of a coca chewer.
The Inca Empire
The Inca Empire managed coca as a strategic state resource. They established large plantations called cocales in the Yungas and strictly controlled the harvest. Coca was distributed to warriors for endurance, to laborers for building temples and roads, and to spiritual leaders for ceremonial use, making it a cornerstone of imperial social integration. The Incas, who ruled over a vast empire in the Andean region from the 13th to the 16th centuries, believed that coca was a gift from the gods.
Ritual, Ceremonial, and Social Uses
In most of the more than 3,100 officially recognized Andean peasant communities in Peru, the traditional uses of coca are integral to daily agricultural activities, to the different forms of mutual aid labor, and to almost all ritual activity, whether with agriculture, divination practices, or rites marking different stages in the life cycle. The plant plays a fundamental role in many traditional Amazonian and Andean cultures, as well as among indigenous groups in the Sierra Nevada de Santa Marta of northern Colombia. Coca leaf offerings are presented to apus (mountains), Inti (the sun), and Pachamama (the earth). Coca leaves are also often read to predict the future, in a way not unlike the reading of tea leaves.
The Amazonian variety, known as coca de la selva, is utilized by indigenous peoples like the Shipibo-Conibo and Ashaninka, whose traditions often involve complex healing rituals overseen by shamans (curanderos), which differ from the more common Andean practice of chewing the leaf or drinking it as tea.
Traditional Medicinal Applications
Coca has been used for centuries as a medicine to treat a wide variety of ailments. The leaves contain chemical substances that can provide relief from pain, altitude sickness, and hunger. Traditional Andean healers, known as curanderos, use coca leaves in their healing practices. Coca leaf products are an integral part of the lives of the Andean peoples from both a cultural and traditional medicine perspective. Coca is also the whole plant from which cocaine is derived. Coca products are thought to be a panacea for health troubles in regions of South America.
Post-Colonial and 19th-Century Western Use
Early research into the pharmaceutically active components of the coca leaf began in the mid-1800s with the first description and crystallization of cocaine. The leaves of the coca plant have been used as a stimulant in South America for over 4,000 years. Cocaine was first isolated from the leaves in the mid-1800s, and was considered safe and used in toothache drops, nausea pills, energy tonics, and the original "Coca-Cola" beverage.
3. Key Constituents and Active Compounds
Total Alkaloid Content
The leaves contain 0.5–1.5% total alkaloid by dry weight, of which the most important of several present is cocaine. Cocaine (methylbenzoylecgonine) is one of at least 12 alkaloids extracted from the leaves of E. coca, all of which have ecgonine as a common constituent. Other alkaloids include cinnamylcocaine, hygrine, tropococaine, truxillines, isotropylcocaine, and cocaicine.
Distribution of Alkaloids Within the Leaf
Detailed analytical work has mapped the within-leaf distribution of these compounds. Each harvested leaf can be divided into primary sections (petiole, base, mid, and anterior) and subsections (lamina periphery, false mid-rib, and true mid-rib) to determine the distribution and content of hygrine, cuscohygrine, trans-cinnamoylcocaine, cis-cinnamoylcocaine, tropacocaine, tropinone, methyl ecgonine, and cocaine. Cocaine, methyl ecgonine, and hygrine were highest in the lamina periphery, at contents of 0.48%, 0.46%, and 0.32% respectively. Trans-cinnamoylcocaine was pre-eminent of the cinnamoylcocaines and was most abundant in the petiole at a content of 0.24%.
Nutritional and Non-Alkaloid Constituents
Coca leaf contains an array of macro- and micronutrients alongside its alkaloid profile. A peer-reviewed study (Penny et al., 2009) measuring eight samples of coca leaves from different Peruvian growing regions using AOAC techniques and inductively coupled plasma–mass spectrometry reported the following concentrations per 100 g dry weight:
- Protein: 20.28 g/100 g DW (with lysine as the limiting amino acid); β-carotene: 3.51 mg/100 g DW; vitamin E: 16.72 mg/100 g DW; trace amounts of vitamin D; calcium: approximately 990–1033 mg/100 g DW (confirmed in two independent laboratories); iron: 29.16 mg/100 g DW; zinc: 2.71–2.63 mg/100 g DW; magnesium: 196–225 mg/100 g DW.
Vitamins identified in coca leaf include β-carotene (provitamin A), vitamin E (α-tocopherol), B vitamins — thiamine (B1), riboflavin (B2), niacin (B3), vitamin C, and vitamin D. Minerals include calcium, iron, magnesium, zinc, potassium, and phosphorus. Coca also contains many flavonoids, polyphenols, and tannins that contribute to its reported medicinal properties.
However, the overall effect gained from using whole coca products may in fact derive from the sum total of all plant constituents, rather than from cocaine alone.
Anti-Nutrient Factors
AOAC techniques were used to measure nutrients alongside nutrient inhibitors — including phytate, polyphenols, oxalic acid, and fiber — all expressed per 100 g dry weight. Like other leafy greens, coca also contains compounds (phytates, oxalates, tannins) that can bind minerals. High fiber and oxalate content may reduce how much calcium or iron is actually absorbed.
4. Mechanisms of Action
Cocaine — The Primary Alkaloid
The major alkaloid, cocaine, exhibits two principal pharmacological mechanisms:
Central stimulant / monoamine reuptake inhibition: Cocaine (benzoylmethylecgonine) is a crystalline tropane alkaloid specifically acting as a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI), functioning as a powerful stimulant of the central nervous system. Its biological function mostly involves blockade of the dopamine transporter protein (DAT), so that dopamine accumulates in the synaptic cleft. The excess of available dopamine for postsynaptic activation mediates the pleasurable effects reported by users and contributes to the addictive potential and toxic effects of the drug.
Local anaesthetic action: Cocaine can exert local anaesthetic action by inhibiting voltage-gated sodium channels, thus halting electrical impulse propagation. It directly blocks dopamine transporters (DAT) and 5-HT serotonin transporters (SERT) to increase dopamine and serotonin concentrations, resulting in its euphoric and addictive properties. At higher concentrations, cocaine blocks voltage-gated Na⁺ channels, thereby inhibiting action potentials in neurons and cardiac myocytes.
Metabolism: Cocaine is metabolized (mostly hepatically) into two main metabolites, ecgonine methyl ester and benzoylecgonine. Other metabolites include norcocaine and cocaethylene, both displaying pharmacological action; cocaethylene constitutes a biomarker for co-consumption of cocaine with alcohol.
Important Distinction: Coca Leaf vs. Purified Cocaine
Medical and physiological effects in the literature concentrate on the pure cocaine isolate. Coca is quite different from cocaine, including in common dosages and safety profiles. Local use patterns of coca are also quite different from those of individuals using the purer isolate. Because of this, it is thought that cocaine studies have limited generalizability to coca.
Metabolic Effects of Whole Leaf Chewing
A human study using cutaneous microdialysis in 10 healthy adult male residents of Cajamarca, Peru (altitude 2,700 m) assessed biochemical changes during standardized cycle ergometer exercise following the chewing of 8 g of coca leaves. Oxygen saturation, blood pressure, and pulse rate did not show any significant changes between the coca-chewing group and controls. Glucose levels showed a hyperglycaemic response. Glycerol, lactate, and pyruvate increased. Glutamate remained unchanged. Similar changes were not seen in the controls. These results suggest that coca leaves blocked the glycolytic pathway of glucose oxidation, resulting in accumulation of glucose and pyruvate. It was proposed that coca leaves blocked the glycolytic pathway at the pyruvate dehydrogenase level, resulting in accumulation of glucose and pyruvate, with the energy requirement for exercise being met instead via beta-oxidation of fatty acids.
5. Scientific Evidence by Area of Use
5.1 Physical Performance and Anti-Fatigue
Traditional claim: That coca leaf chewing reduces fatigue and increases work capacity, especially in agricultural laborers and mine workers at altitude.
Human / clinical evidence: The primary human study cited in the peer-reviewed literature is a small open-label experiment (n = 10 healthy adult male residents of Peru at 2,700 m altitude), using cutaneous microdialysis and a stationary cycle ergometer. The experimental findings suggested that chewing coca leaves gives a beneficial effect during performance of exercise and that the beneficial effects are felt over a prolonged period of sustained physical activity, possibly giving users energy to function at a sustained level over long periods of time. However, this was a small, uncontrolled study without blinding and its results should be considered preliminary.
Counterpoint from earlier literature: Although chewing of coca leaf diminishes fatigue and by exerting a stimulating effect may increase the output of work within a short period of a particular experiment, the result in no way shows that coca users are capable of doing more work and achieving a greater output over the protracted period required for their customary tasks.
Evidence strength: Preliminary and limited. There are no large, randomized, double-blind controlled trials on coca leaf and physical performance. The mechanistic finding — a metabolic shift toward fat oxidation — is intriguing but has not been replicated in adequately powered trials.
5.2 Acute Mountain Sickness (AMS)
Traditional claim and cultural use: Coca leaf tea and leaf chewing are widely offered to travelers in Andean countries as a remedy for altitude sickness (AMS). Coca leaf tea has been anecdotally mentioned by travelers and climbers to South American countries for the presumed symptomatic relief of acute mountain sickness.
Human / clinical evidence: A 2022 prospective cohort study published in the Journal of Travel Medicine enrolled 142 language students (median age 21 years, 57% female) ascending rapidly to approximately 3,400 m in Cusco, Peru. Participants used various strategies to prevent AMS: 34% drank coca leaf tea. Thirty-nine percent had AMS. In multivariate analysis, obesity (OR 14.45) and female sex (OR 4.32) were associated with increased risk of AMS; taking acetazolamide (OR 0.13) was associated with decreased AMS risk. Consumption of coca leaf tea was not associated with decreased risk of AMS.
By its very nature, there may never be scientific "proof" that coca leaves do or do not work for travelers at altitude, but a solid knowledge of coca, and how it differs from cocaine, provides a platform for informed opinions and appropriate critical views on the current confusing and contradictory legal situation.
Evidence strength: The available clinical evidence does not support coca leaf as an effective prophylactic or treatment for AMS. The primary methods of preventing AMS are properly managed acclimatisation and the use of acetazolamide; other pharmacological and natural measures require further research. Evidence for coca in this context remains largely anecdotal and observational.
5.3 Nutritional Contribution
Human / analytical evidence: The systematic nutritional study by Penny et al. (2009), published in Food and Nutrition Bulletin, assessed eight samples of coca leaves grown across different regions of Peru. Results were compared with other edible leaves, and the nutrients in coca powder (5 g) and bread made with coca were compared with normal portions of alternative foods. Two spoonfuls of coca leaf flour would satisfy less than 10% of dietary intakes for schoolchildren and adults for critical commonly deficient nutrients in the diet. Additionally, two spoonfuls of coca leaf flour would satisfy less than 10% of dietary intakes for schoolchildren and adults for critical commonly deficient nutrients in the diet. Coca leaves do not provide nutritional benefits in practically consumed quantities, in the view of those authors.
In contrast, larger daily consumption amounts associated with traditional heavy chewing (Andean coca chewers may use 30–60 g/day, which could supply large amounts of calcium and iron; an Andean source noted that 60 g of coca leaf alone "more than satisfies [the chewer's] requirements for calcium.").
Evidence strength: The nutritional content of the dry leaf is well-characterized analytically. However, actual bioavailability from normal consumption patterns (tea infusion, small quantities of chewed leaf) is uncertain because of the anti-nutrient factors (phytates, oxalates) present and the fact that formal bioavailability trials in humans have not been published.
5.4 Appetite and Hunger Suppression
Traditional Andean use for suppressing hunger during long workdays at altitude is well documented ethnographically. At the pharmacological level, cocaine is known to suppress hunger and appetite by increasing co-localization of sigma σ1R receptors and ghrelin GHS-R1a cell surface receptors, thereby increasing ghrelin-mediated signaling of satiety. Whether this mechanism operates at the low systemic alkaloid levels achieved by leaf chewing has not been established in controlled clinical trials. No published randomized clinical trials specifically assessing appetite suppression from whole coca leaf in humans were identified.
5.5 Local Analgesia / Pain Relief
Cocaine — the primary alkaloid — was among the earliest and most effective of local anaesthetics, but is now superseded by derivatives and others with better characteristics. Traditional use of coca for dental pain, headache, and muscular pain is documented across Andean and Amazonian indigenous traditions. The mechanism of local anaesthesia via sodium-channel blockade has been thoroughly established for purified cocaine. No controlled clinical trials exist specifically examining the topical or systemic analgesic properties of crude coca leaf preparations in humans.
5.6 Cytotoxic / Anti-cancer Properties (In Vitro Only)
Cytotoxic activity has been reported in extracts from various species of the Erythroxylum genus. The presence of quantified flavonoids and polyphenols derived from cinnamic acid and shikimic acid precursors suggests activation of the shikimate metabolic pathway, which is responsible for the biosynthesis of compounds with cytotoxic properties; the trimethoxycinnamate group at the C-6 position has been associated with malignant cell growth inhibition and enzymatic suppression in humans. These findings are preliminary in vitro results only and have not been studied in human clinical trials.
6. Body Systems and Health Areas of Association
Central Nervous System
The predominant pharmacological effects of coca's principal alkaloid bear on the CNS. Cocaine inhibits the reuptake of catecholamines, which increases the activity of sympathetic synapses; this stimulation also occurs in the brain, causing euphoria, garrulousness, and increased motor activity. Cocaine also decreases fatigue and is abused as a stimulant. In the context of traditional whole-leaf use, the systemic absorption of cocaine is substantially lower than with isolated cocaine use.
Cardiovascular System
Cocaine also causes vasoconstriction, thus reducing bleeding during minor surgical procedures. The pharmacology of cocaine is complex, with several organ systems affected simultaneously. Systems affected by acute and chronic use of cocaine include psychological, neurological, renal, cardiac, pulmonary, gastrointestinal, obstetrical, and otolaryngological ones. Again, these effects are predominantly documented for purified cocaine and their relevance to whole-leaf traditional use is not directly established.
Musculoskeletal and Metabolic
The human physiology study described above (PMC3001837) suggested a shift in energy metabolism away from glycolysis and toward fat oxidation during exercise. The glycerol released was also accumulating since its pathway for oxidation was proposed to be blocked. These experimental findings suggest that chewing coca leaves gives a beneficial effect during exercise performance, and that the beneficial effects are felt over a prolonged period of sustained physical activity.
Gastrointestinal
Traditional Andean medicine uses coca tea for gastrointestinal complaints including nausea, stomach pain, and as a digestive aid. This application is reported in ethnographic and anthropological literature but has not been evaluated in controlled clinical trials.
7. Dosages Reported in Scientific Studies
The following doses appear in the cited literature. They are reported as recorded, without endorsement:
- Leaf chewing (exercise physiology study): Subjects were given 8 g of coca leaves to chew with a small amount of lime, and then placed on a cycle ergometer for 20 minutes.
- Traditional daily chewing (mine workers): A study of over 3,000 coca users found that mine workers, typically the largest consumers, chew roughly 13 ounces (368.5 grams) per week. This would mean an average user would extract approximately 3.9 net grams of the alkaloids contained in coca per week, giving a maximal total dosage of roughly 200–300 mg per 24-hour period.
- Traditional daily chewing (general estimate): In comparison to modern use of cocaine isolates, the amount used by native peoples was and remains quite low, with an estimated 60 grams of coca leaf chewed per day. A coca leaf typically contains between 0.1% and 0.9% cocaine.
- Coca tea cup for forensic/toxicological study: Urine samples were collected over 72 hours after consumption of a single cup of coca tea containing 3.8 mg of cocaine from five volunteers.
- Nutritional assessment: The nutrient contributions of coca powder (5 g) and bread made with coca were compared with those of normal portions of alternative foods; two spoonfuls of coca leaf flour would satisfy less than 10% of dietary intakes for schoolchildren and adults for critical commonly deficient nutrients.
8. Safety, Toxicology, and Interactions
Acute Toxicity of Whole Leaf
In the WHO 48th ECDD 2025 critical review, coca leaf was assessed to exhibit low acute toxicity in animal models. No fatal overdoses have been reported from traditional use. Adverse effects are primarily localized (e.g., oral mucosa irritation) and dose-dependent. Coca leaf use is not associated with significant dependence or abuse potential.
Dependence Potential
There is no evidence in the literature to support habitual whole coca use causing addiction or withdrawal physiology, in contrast to that of purified cocaine. The consumption of coca leaves is a traditional practice that generates legal problems in some Latin American countries; it is a practice that has not been scientifically proven to cause any harm.
Drug Testing and Forensic Implications
A critical safety consideration for any person consuming coca leaf preparations is the forensic consequence: coca tea ingestion has resulted in a positive urine assay for cocaine metabolite. Detailed forensic data were provided in a 2022 study: cocaine was detectable in urine for 20 hours (concentration range 6–91 ng/mL), and its metabolites benzoylecgonine and ecgonine methyl ester were detectable for 70 and 60 hours respectively, after consumption of a single cup of coca tea. Hair samples analysed one month after the consumption of a single coca tea cup were negative for cocaine.
The consumption of coca leaf products, a traditional practice in several Latin American countries, raises forensic challenges in distinguishing legal consumption from illicit cocaine use, with implications for drug-impaired driving (DUID) and workplace drug testing (WDT) contexts.
Cardiovascular Considerations
Acute cocaine intoxication affects several organ systems and presents with a wide range of symptoms. Selective beta-blockers should be avoided in the acutely intoxicated patient secondary to the risk of unopposed alpha-mediated coronary and peripheral vasoconstriction. These cautions apply to the purified alkaloid at pharmacologically relevant doses; the systemic cardiovascular effects of traditional whole-leaf preparations at typical consumption amounts are not well characterized in controlled human studies.
Nutrient Inhibitors
Coca also contains compounds (phytates, oxalates, tannins) that can bind minerals. High fiber and oxalate content might reduce how much calcium or iron is actually absorbed. This diminishes the practical nutritional value of the leaf, particularly when consumed in small amounts as tea.
9. Legal Status and International Regulation
Coca leaf is currently listed under Schedule I of the 1961 Single Convention on Narcotic Drugs — substances whose liability to abuse is considered an especially serious risk to public health. The international prohibition of the coca leaf, established by the 1961 United Nations Single Convention, which did not distinguish it from cocaine despite traditional Andean uses, has been widely contested. Since the mid-20th century, traditional practices involving coca leaves have been restricted by the international drug control regime; the WHO recommended its inclusion in Schedule I, on the same level as cocaine, based on a controversial report influenced by cultural and racial prejudices.
In December 2025, following a comprehensive scientific review: The WHO's Expert Committee on Drug Dependence (ECDD) recommended that coca leaf remain under Schedule I of the 1961 Single Convention on Narcotic Drugs, while concluding at its 48th ECDD meeting that although traditional coca-leaf chewing and tea consumption do not pose major public-health risks, the leaf should remain under a strict level of international control, with a framework that allows for legitimate medical, scientific, and traditional use in countries where it is produced, while controlling diversion for cocaine production.
The use of coca leaf is permitted by law in Argentina, and the Bolivian legal system recognizes its ancestral character; in Peru, its cultivation and sale are also permitted. Outside South America, coca leaf is generally illegal or heavily restricted, often treated similarly to cocaine.
References
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