Twenty-seven patients with fasciolasis which was diagnosed through biliary drainage indicated in patients with upper digestive symptoms, particularly of the gastroduodenal portion are presented. The great significance of this procedure in the positive diagnosis of this disease is stressed. The clinical and humoral pictures of these patients are analyzed, and emphasis is made on their poorly defined clinical picture as well as on the little effectiveness of the humoral tests and parasitological studies performed on them. The results of liver macro and microscopic studies on a group of these patients are shown, and the fact that only one patient had lesions attributable to parasitic infestation is pointed out.