Pithomyces chartarum occurs worldwide but is a problem predominantly where farm animals are intensively grazed, especially in New Zealand. The spores of the fungus release the mycotoxin Sporidesmin in the gastrointestinal tract, causing a blockage in the bile ducts that leads to injury of the liver. Bile, chlorophyll and other waste products consequently build up in the bloodstream causing photo sensitivity of the skin especially that exposed to direct sunlight. This in turn causes severe skin irritation that the animal attempts to relieve by rubbing its head against available objects, resulting in peeling of the skin.