We report here the long-term sequelae in 22 patients with L-tryptophan-induced eosinophilia-myalgia syndrome (EMS). The mean follow-up was 23 months (range, 5 to 40 months). Myalgia, rash, pruritus, edema, and respiratory symptoms often improved with the use of corticosteroids, but fatigue and weakness persisted in most cases. Other abnormalities that commonly persisted were arthralgia, muscle-cramping, peripheral neuropathy, and thickened skin. One patient had chronic pulmonary hypertension. These findings indicate that for most patients, EMS is a chronic disorder.