We report the results of short-term antibiotic treatment in 19 patients with Whipple's disease (WD). The diagnosis was based on clinical features and on a characteristic small bowel biopsy. Patients received treatment for a mean of 7.9 weeks (range 4-20). Fourteen were treated with de-methyl-chlortetracycline (600 mg/day), and 1 also received chloramphenicol (1 g/day); 1 was treated with ampicillin (2 g/day), and 4 were treated with amoxicillin (1.5 g/day). In all patients, the clinical response was rapid and excellent, body weight increased significantly, diarrhea subsided, and fecal fat values returned to normal. Intestinal biopsies obtained after treatment was completed showed significant improvement based on a decrease in the number of macrophages staining positive with periodic acid-Schiff (PAS), normalization of villous structure, and decreased dilatation of lymphatic channels; free bacilli were absent, as shown both by light and electron microscopy. Seventeen patients have been followed for a mean of 99.4 months (range 6-300). Two died 30 and 72 months after diagnosis of Whipple's disease, 1 of laryngeal carcinoma and the other of colonic carcinoma. Fifteen patients are in excellent health. Three patients treated with tetracycline have had clinical and/or histologic relapses. In our experience, short-course antibiotic treatment with tetracycline or ampicillin and derivatives can be effective in WD, with few relapses and excellent outcome. No neurologic symptoms, either initially or during follow-up were observed.