We describe a patient with eosinophilic gastroenteritis whose symptoms included severe watery diarrhea (1.5 l/d), abdominal cramps, and weight loss. Biopsies revealed massive eosinophilic inflammation of the entire gastrointestinal tract. The total plasma eosinophilic count was elevated by up to 30%. Infectious etiologies and chronic inflammatory bowel disease had been ruled out. By use of the somatostatin analogue octreotide the diarrhea decreased immediately in a dose-dependent fashion and the patient recovered within twelve days. In this case octreotide was helpful in controlling severe diarrhea and limiting the subsequent necessary i.v. fluid replacement.