# Soya (Glycine max) *Soy bean, soja; *Glycine max* (L.) Merrill, Stuart’s *Glycine hispida*; Chinese *shu*, *ta-tou*, the ‘great bean,’ and *hei-tou*, the black bean; in pharmacy soya lecithin and refined soya-bean oil* **Known today as.** *Glycine max*, an annual herb of the legume family, cultivated, whose pods hold one to four round seeds of many colours. Stuart, writing in 1911, calls it the Chinese and Japanese soy bean, “known in China from ancient times,” and always considered by the Chinese “the most important of the cultivated leguminous plants.” Its seed is 35 to 40 per cent protein and 15 to 20 per cent fat, the source of the oil and of the lecithin that medicine uses. Kind: Plant > **Caution.** Soya lecithin is not for anyone allergic to soya, to peanut or to other legumes, or to birch pollen; allergic reactions to it, including severe anaphylaxis and angioedema, have been reported, with skin reactions and stomach upsets. The bath oil is not for open wounds, large skin injuries, acute skin disease, high fever, severe infection, severe circulatory disorders, or heart failure; in the eye it can cause keratitis, and swallowed it can cause nausea, vomiting, and diarrhoea, with a risk of inhaling vomit, so vomiting should not be induced. Soya lecithin is not for children under twelve. ## What was it used for? A food first: in China and Japan, Stuart writes, it made “bean oil,” “bean-curd,” and “soy,” three products of almost universal use in Eastern cooking. In medicine it was the black bean that counted. Its frequent use was thought to give “strength and vigor, albeit with heaviness”; it was taken for “an admirable counter-poison” against most of the vegetable poisons, aconite and croton among them, and the green beans chewed to a pulp were laid on smallpox ulcers and ulcers of the cornea, the bruised leaves on snake bite. ## What does modern science say? The European Medicines Agency’s herbal committee split the plant in three. Soya lecithin, a mixture of phospholipids in which phosphatidylcholine averages 76 per cent, it accepts as a traditional herbal medicine for the relief of temporary fatigue and a sense of weakness; refined soya-bean oil, about half linoleic acid, as a traditional bath additive for dry skin with mild recurrent eczema; both “exclusively based upon long-standing use” (monographs of 2017). For the isoflavone-rich extracts of the bean germ it adopted no monograph at all: neither a recognised efficacy nor the required period of traditional use was established (public statement of 2018). A Cochrane review of soy infant formula concluded in 2006 that it “cannot be recommended for prevention of allergy or food intolerance in infants at high risk of allergy or food intolerance.” ## Pharmacognosy and toxicology - **phosphatidylcholine**: on average 76 per cent of soya lecithin - **linoleic acid**: about half of the refined oil - **isoflavones**: in the extracts of the bean germ **Mechanism.** Not established in the sources read for this entry. **Standing.** European Union herbal monographs (2017): traditional use, “exclusively based upon long-standing use,” of soya lecithin for temporary fatigue and of refined soya-bean oil as a bath additive for dry skin. For the isoflavone extracts there is no monograph (public statement of 2018). ## What lore surrounds it? Stuart notes that the name ‘great bean’ belongs to the plant and not to its seeds, which are quite small, and that the classical character for it is ancient, with compound names as old. The heaviness the black bean gave the body was, he says, the only objection the Chinese offered to its use. ## What did the older authorities say? **G. A. Stuart, *Chinese Materia Medica*.** The Chinese distinguish the varieties by the colour of the seed, black, white, yellow, grey, azure, and spotted: “The black sort is used in medicine, and the yellow is specially valued in the preparation of bean-curd and soy.” The black kind was little eaten, “as it is thought to render the body heavy,” for the Chinese, he explains, favoured things that give lightness to the body over those that promote flesh and sluggishness. The beans went into prescriptions for difficulties after childbirth and for sexual disorders, but always with other active drugs, so that, he judged, “the beans play no very important part in these prescriptions.” ## Sources - Stuart, G. A. (1911). *Chinese Materia Medica: Vegetable Kingdom*, “Glycine hispida.” Internet Archive, chinesemateriame00stuauoft. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Lecithinum ex soya (Soya-bean lecithin)*. EMA/HMPC/220599/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Soiae oleum raffinatum (Soya-bean oil)*. EMA/HMPC/338914/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Public statement on Glycini semen (Soya)*. EMA/HMPC/461814/2016, 05 June 2018. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Lecithinum ex soya*. EMA/HMPC/220598/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Soiae oleum raffinatum*. EMA/HMPC/338915/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Glycini semen*. EMA/HMPC/461813/2016, 05 June 2018. - Osborn DA & Sinn J (2006). Soy formula for prevention of allergy and food intolerance in infants. *The Cochrane database of systematic reviews*. PMID 17054183. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Lecithinum ex soya (Soya-bean lecithin)*. EMA/HMPC/220599/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Soiae oleum raffinatum (Soya-bean oil)*. EMA/HMPC/338914/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Public statement on Glycini semen (Soya)*. EMA/HMPC/461814/2016, 05 June 2018. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Lecithinum ex soya*. EMA/HMPC/220598/2016, 31 January 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Soiae oleum raffinatum*. EMA/HMPC/338915/2016, 31 January 2017. --- *Soya.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/soya Historical description, not medical advice.