Fluke (fascioloides) is a parasitic liver disease that infests deer in the flatland forest and wetland plains hunting areas, rarely in the mountains. The causes of this disease are two types of liver fluke which belong to a group of flatworms: the large fluke (Fasciola hepatica seu Distomum hepaticum) and a small fluke (Dicrocoelium dendriticum). The aim of this study was to determine: (a) the impact of disease progression on the deer population, (b) optimal methods of drug treatment, (c) the number of infested deer in population after continuous drug treatment over several years and (d) the impact of this deer disease on the quality of tourism offer in the area of the Special Nature Reserve “Gornje Podunavlje”. The hunting experts estimate, based on established health condition of the hunted deer, that fluke infestation has steadily increased from initial 20% up to 90%. Fluke has, undoubtedly, contributed to the overall health status deterioration of deer population, with very high mortality rate. The situation has significantly changed in 2006, when the deer were treated with an anti-parasitic preparation (Albendazole), mixed in concentrated food and salt. This treatment proved to be a very successful therapy for Fluke disease.