A phytotoxin is a toxic compound made by a plant, part of the botanical arsenal against herbivores, insects, and pathogens. Familiar food examples include solanine and chaconine in green potatoes, cyanogenic glycosides in bitter almonds and cassava, lectins in raw kidney beans, and pyrrolizidine alkaloids in certain herbal teas. Concentrations rise when plants are stressed, damaged, or improperly stored, which is why greened potatoes and sprouted tubers are trimmed generously or discarded. Unlike pesticide residues, phytotoxins are inherent to the food, and food safety manages them through breeding low-toxin varieties, processing methods like soaking and boiling beans, and regulatory limits for compounds like erucic acid and coumarin. The dose makes the poison: many phytotoxins are harmless at normal intakes and some, like glucosinolates, may even be beneficial.