Eosinophilia-myalgia syndrome, a recently described illness, reached epidemic proportions in 1989 and was linked to the ingestion of L-tryptophan containing trace amounts of several contaminants. Eosinophilia-myalgia syndrome shares many clinical and pathologic similarities with toxic-oil syndrome, an epidemic linked to the ingestion of adulterated cooking oil that occurred in Spain in 1981, and to diffuse fasciitis with eosinophilia, a condition first described in 1974. Over the past year, much work has been done in understanding the etiology and pathogenesis of eosinophilia-myalgia syndrome and toxic-oil syndrome. Follow-up data detailing the long-term sequelae and mortality rates for these two conditions are becoming available. The results from these studies are reviewed in this paper.