Protoanemonin is a toxin found in all plants of the buttercup family (Ranunculaceae). On maceration, for example when the plant is wounded, it is produced by an enzymatic process from the glucoside ranunculin. It is the lactone of 4-hydroxy-2,4-pentadienoic acid. A wounded plant releases the substance, causing itch, rashes or blistering on contact with the skin or mucosa. Ingesting fresh Ranunculaceae can lead to nausea, vomiting, dizziness, spasms, or paralysis. When drying the plant, protoanemonin comes into contact with air and dimerizes to anemonin, which is further hydrolyzed to a non-toxic carboxylic acid. Protoanemonin is a toxic metabolite which may be formed during the degradation of some chloroaromatic compounds, such as polychlorinated biphenyls, by natural microbial consortia. Protoanemonin can be transformed by dienelactone hydrolase of Pseudomonas sp.