L-tryptophan use and the eosinophilia-myalgia syndrome

We present a case of the eosinophilia-myalgia syndrome in a patient taking large doses of L-tryptophan for sedation. He developed the now-classic findings of myalgias, skin changes, and marked eosinophilia. This syndrome was first recognized in late 1989, and epidemiologic studies have demonstrated an association of the clinical syndrome with ingestion of L-tryptophan. The mechanism of toxicity remains unknown. Casual use of L-tryptophan has been diminished by its rapid removal from the nutrition counter of health food stores.