Peony, particularly the roots of Paeonia lactiflora and related species, has been used in traditional Chinese medicine (TCM) for centuries. In TCM, peony (known as "Bai Shao" for white peony or "Chi Shao" for red peony) is believed to "nourish the blood," "soften the liver," and "alleviate pain." Historically, it has been included in herbal formulas intended to address various inflammatory conditions, including those involving swelling and discomfort, which sometimes were interpreted as "swollen glands" or lymph nodes. However, these traditional uses do not precisely map to modern medical understanding of lymphadenopathy or lymphatic disorders. The rationale in TCM is based more on the herb's perceived ability to reduce "heat" and "toxicity" in the body rather than direct evidence concerning lymph tissue or immune function.

Scientifically, there is limited evidence to support the use of peony for swollen lymph glands. Most research focuses on its anti-inflammatory and immunomodulatory effects, but studies rarely target lymphatic swelling specifically. The evidence is thus mainly traditional, with little to no direct clinical research validating its efficacy for swollen lymph nodes in modern medical terms. The traditional rating is low (1), as the connection is indirect and not robustly documented even in historical sources.