Willow, Wild Cherry, Sweet Birch, Sugar Maple & Alder — Milk & Honey Herbs

As Kerry Bone and Simon Mills explain in their book, The Essential Guide to Herbal Safety, “although hydrocyanic acid (cyanide) is a poison, oral intake of prunasin is not necessarily toxic, as hydrolysis in the digestive tract or by the liver leads to a slow release of very low levels of hydrocyanic acid, which can readily be detoxified by the body.” The herbalists Michael Moore wrote, “…chokecherry bark presents a potentially dangerous group of physiological responses in a completely safe package.  The shadow of hydrocyanic acid is still there… but it is completely safe and diffused.  The mechanism might make a pharmacologist cringe because it so closely that of true cyanotic poisons, but once again, it is safe and reliable for even small children.  It has been used safely for centuries, probably millennia, in such diverse places as Siberia, Germany, the lakeside villages of Mandan, the mountains of northern New Mexico, and the valleys of Kentucky.” And finally, herbalist Lisa Ganora, author of Herbal Constituents: Foundations of Phytochemistry writes, “Wild Cherry bark contains extremely low levels of prunasin which is classified as a ‘cyanogenic glycoside’, meaning it can release hydrocyanic acid (HCN) – however, since cyanide is a natural waste product of protein metabolism in the body, we have endogenous enzymes that detoxify it – they can handle up to 1 mg/hour with no adverse effects to the body at all.  It’s not a persistent toxin.  Also, the human digestive system has suboptimal pH for cyanide formation, meaning that of the amount of glycoside you do ingest, not much HCN is actually released. So, Cherry bark per se is not a problem.  Browsing on wilted Cherry leaves will kill a cow or horse though – because there are much higher levels of cyanogenic glycosides in the leaves, and wilting is an enzymatic process that degrades them, releasing a large amount of HCN.  Also, the animal is ingesting large quantities of plant material.  This came to the attention of veterinary toxicologists during the depression in the Appalachians, when the stock sometimes had nothing else to eat.”