EN
The course of Fasciola hepatica infection was studied by the coproscopical methods in two farms of Southern Poland. The extensity of infection reached between 84 to 94 per cent. The experimental studies has been done on 54 lambs at the average weight of 21.50 kg. The lambs were divided in 3 groups with 18 lambs in each. In the first group were non-infected animals; second group was infected with 200 metacercaria and treated with Fasinex (10 mg/kg body weight) 6 weeks after infection. The third group was infected with 200 metacercaria, but has not been treated with Fasinex. The best results were obtained in the first group. In this group the weight gain was about 4 kg (14.7 per cent) higher comparing with the group third (infected, non-treated) group. The weight gain of group two (infected and treated) was 2.42 kg (11.0 per cent) higher as in group third group.