Facial eczema (FE) is a disease which causes lowered production and sometimes death from liver damage. Fungal spores produced by the fungus Pithomyces chartarum growing on pasture produce a toxin which, when ingested by cattle, damage the liver and bile ducts.

The damaged liver cannot rid the body of wastes and a breakdown product of chlorophyll builds up in the body causing sensitivity to sunlight, which in turn causes inflammation of the skin.