The dermatitic properties of black bryony (Tamus communis L.).

The skin irritant properties of both the juice expressed from the ripe berries and the slimy mucilage present in the rhizomes of black bryony (Tamus communis L.) were investigated. The dermatitis produced on human skin after gently rubbing in either the berry juice or the rhizome mucilage was found in both cases to be a result of mechanical irritation, being produced by penetration of the skin by minute needle-like crystals of calcium oxalate. Scanning electron micrographs supporting this conclusion are presented. Chemical investigation of the rhizome mucilage confirmed the presence of histamine. The rôle of histamine in the production of skin irritation following contact with the rhizome mucilage is discussed.