Tryptophan-induced eosinophilia-myalgia syndrome Eight patients who became ill while taking tryptophan had myalgia, fatigue, rash, fever, edema, alopecia, arthralgias, diminished joint motion, skin tightening, muscle cramping, and distal paresthesias. Three had shortness of breath, and one had pulmonary hypertension. Laboratory abnormalities included peripheral eosinophilia, leukocytosis, thrombocytosis, raised erythrocyte sedimentation rate, and elevated serum levels of aldolase, lactate dehydrogenase, and liver enzymes. Of 4 chest radiographs, 3 were abnormal. Of 5 skin and muscle biopsies, 4 showed sclerosis or mixed inflammatory cell infiltration of the dermis, subcutis, and fascia. Eosinophils were often present, but vasculitis was absent. Muscle inflammation was minimal. We conclude that the "eosinophilia-myalgia syndrome" is related to the ingestion of tryptophan and that abnormalities in the secretion of lymphokines may be important in its pathogenesis. 