# Oat (Avena sativa) *Oats, groats, oatmeal; old English haver or hafer corn, Welsh *hever*; *Avena sativa* of Linnaeus; the Greek *bromos* of Dioscorides; in pharmacy *Avenae herba*, the green herb, and *Avenae fructus*, the grain* **Known today as.** *Avena sativa*, the common oat, a cereal grass up to four feet high with rough, veined leaves and a loose panicle of pendulous two-flowered spikelets. Grieve notes some twenty-five varieties in cultivation, and that the grain stripped of its husk is groats, and groats crushed are Embden groats. Medicine uses both the grain and the green herb cut before flowering. Kind: Plant > **Caution.** The European agency advises caution in coeliac disease, since the protein content of the preparations is not known, and does not recommend the herb for children under twelve. Skin reactions may occur in people with atopy or contact dermatitis. Grieve advised against oatmeal in indigestion with acidity of the stomach. ## What was it used for? Food for the sick, first. Grieve gives oatmeal gruel, boiled down with sugar, lemon, wine, or raisins, as “a mild nutritious aliment, of easy digestion in inflammatory cases and fevers,” useful after childbirth and as a demulcent enema, and boiled thick as a poultice; a tincture of the grain she gives as a nerve and uterine tonic. Dioscorides made poultices of it like barley, a porridge to bind the bowels, and a cream sipped for a cough. ## What does modern science say? The European Medicines Agency’s herbal committee accepts the green herb as a traditional herbal medicine, “exclusively based upon long-standing use,” for mild symptoms of mental stress and to aid sleep, and the grain, in a bath, for minor skin inflammation such as sunburn and to aid the healing of minor wounds (monographs of 2008). Its assessment report notes the indole alkaloid gramine, thought responsible for a weak sedative effect, and the avenanthramides, polyphenols found in no other cereal. As food the grain has been tested: a 2024 meta-analysis of 17 trials in 1,731 people with abnormal blood fats found that oat products “may reduce TC and LDL-C, but have little effect on TG, HDL-C, and major cardiovascular events.” ## Pharmacognosy and toxicology - **gramine**: an indole alkaloid, thought responsible for a weak sedative effect - **avenanthramides**: polyphenols found in no other cereal **Mechanism.** Not established in the sources read for this entry. **Standing.** European Union herbal monographs (2008): traditional use, “exclusively based upon long-standing use,” of the green herb for mild mental stress and sleep, and of the grain in a bath for minor skin inflammation and wounds. ## What lore surrounds it? Oats had a poor name in Rome: Folkard quotes Pliny’s *Primum omnium frumenti vitium Avena est*, the first disease of corn is the oat. In Scandinavian myth, he writes, the ‘hafer’ of the evil Loki meant the devil’s oats, a name for all herbs hurtful to cattle, and in the belief that Loki sowed weeds among the good seed he finds the probable origin of the English saying “He is sowing his wild Oats.” A Ukrainian tale has God, pressed by the Devil for a present, give him the oats, and St. Paul set out to win them back. ## What did the older authorities say? **Dioscorides.** *Bromos*, which the modern translation identifies with the oat, is a grass like wheat in the leaf, with knots, and seed borne at the top in husks he likens to “two-footed little locusts.” **Mrs. M. Grieve.** The husk of the grain, she reports, holds an alkaloid that stimulates the motor nerves and “in horses causes excitement,” and oatmeal is to be avoided in dyspepsia with acidity of the stomach. ## Sources - Grieve, M. *A Modern Herbal*, “Oats.” As published on botanical.com. - Dioscorides. *De materia medica*, 2-116, in the modern English version of T. A. Osbaldeston and R. P. A. Wood (Johannesburg: Ibidis, 2000), after Goodyer’s translation of 1655. Internet Archive. - Folkard, R. (1884). *Plant Lore, Legends, and Lyrics*, “Oats.” Project Gutenberg, 44638. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Avenae herba (Oat Herb)*. EMEA/HMPC/202966/2007, 4 September 2008. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Avenae fructus (Oat Fruit)*. EMEA/HMPC/368600/2007, 4 September 2008. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Avenae herba*. EMEA/HMPC/202967/2007, 4 September 2008. - Li A, et al. (2024). Efficacy of oats in dyslipidemia: a systematic review and meta-analysis. *Food & function*. PMID 38441173. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Avenae herba (Oat Herb)*. EMEA/HMPC/202966/2007, 4 September 2008. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Avenae fructus (Oat Fruit)*. EMEA/HMPC/368600/2007, 4 September 2008. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Avenae herba*. EMEA/HMPC/202967/2007, 4 September 2008. - Li A, et al. (2024). Efficacy of oats in dyslipidemia: a systematic review and meta-analysis. *Food & function*. PMID 38441173. --- *Oat.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/oat Historical description, not medical advice.