Fusarium, a fungus, produces a potent mycotoxin that, when ingested with contaminated cereal grains, produces a serious illness in man called alimentary toxic aleukia (USSR) and Akakabi-byo (Japan). The illness includes gastrointestinal symptoms and weakness and if ingestion of Fusarium contaminated grain persists, culminates in aplastic anemia. A 66-year-old woman had Eaton-Lambert syndrome and a clinical course similar to alimentary toxic aleukia. Several months before her death, pancytopenia, initially thought guanidine-induced, developed and progressed to aplastic anemia despite discontinuation of guanidine 2 1/2 months before death. Autopsy showed numerous granuloma in the liver, spleen, esophagus, and cecum from which Fusarium oxysporum was isolated. Although the unique finding of systemic fusariosis may relate to altered host resistance terminally, a causal relationship with her defect of neuromuscular transmission and/or aplastic anemia is a distinct possibility.