 Extracts of the puffball have strong antitumor activity in mouse models attributable to protein-bound polysaccharides, the compounds calvatan, craniformin, and a tautomer of rubroflavin. Calvatan is thought to act by stimulating the immune response, rather than by killing cells. Craniformin, originally reported in 1997, is an azoformamide compound. Three sterol compounds have been identified from the fungus: ergosta-4,6,8 (14), 22-tetraene-3-one, ergosta-7,22-diene-3-ol, and ergosterol peroxide.
