To the Editor.— Agent Orange is an herbicide containing equal parts of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid. It was used extensively in Vietnam as a defoliant. A toxic contaminant is dioxin, 2,3,7,8 tetrachlorodibenzo-p-dioxin. A ten-month study of 78 Vietnam veterans who claimed exposure to Agent Orange yielded many findings: 85% of the men experienced a rash that was resistant to treatment. Using immunofluorescence in one patient, a skin biopsy specimen showed intraepithelial and intercellular IgA, IgG, and IgM. In 53% of the patients, the rash was aggravated by sunlight. Joint pain occurred in 71%, stiffness in 59%, and swelling in 45%. Hypersomnolence occurred in 44% of the men and extreme fatigue in 80%. Sinus bradycardia and premature ventricular contractions were not infrequent. Persistent neurological complaints were tingling (55%), numbness (60%), dizziness (69%), headache (35%), and autonomic dyscontrol (18%). Severe psychiatric manifestations were depression (73%), suicidal attempts (8%), and