Houttuynia cordata, known as "dokudami" in Japanese and widely used in traditional Chinese medicine (TCM), has long been employed for its purported detoxifying, anti-inflammatory, and immune-supporting properties. In TCM, Houttuynia is classically prescribed to treat "heat toxicity" and conditions associated with swelling, including swollen lymph nodes (often described as "scrofula" or "yin swelling"). Herbal practitioners believe it helps to "clear heat" and "eliminate toxins," which, in TCM theory, are thought to contribute to lymphatic congestion and glandular swelling.

Scientifically, there is very limited direct evidence supporting Houttuynia's efficacy specifically for swollen lymph glands. Some modern pharmacological studies have found that extracts of Houttuynia cordata possess anti-inflammatory and immunomodulatory effects in vitro and in animal models. However, these studies have not focused specifically on lymphadenopathy or swollen glands in humans, and clinical trials for this indication are lacking. Therefore, while laboratory data suggest potential mechanisms relevant to inflammation, the use of Houttuynia for swollen lymph nodes remains primarily rooted in traditional usage rather than established scientific validation.

In summary, Houttuynia cordata is traditionally used to address swollen glands in East Asian herbal medicine, but scientific evidence for this specific application is limited.