The Digenetic Trematodes include a vast majority of parasitic organisms which cause diseases in their hosts. The Main intermediate hosts for majority of Digenetic Trematodes are snails represented in following genus: Bulinus, Biomphalaria, Oncomelania and Lymnaea. The relationship between snail host and parasite is very complex and still not fully explained. In this paper, the focus is on life cycles of two parasitic Trematodes, Fasciola and Schistosoma with their intermediate hosts required for parasitic development. Understanding the characteristics and life cycle of parasites including the ecology of disease bearing snail hosts, is crucial for successfully controlling the spreading of disease and negativ socio-economic impact in disease infected countries. In conclusion, the methods used for preventing the epidemic and regulating snail populations have been considered. From mechanical methods used in extracting specified infected snails to non-selective, invasive, chemical methods which can cause degradation of entire ecosystem. Parasitism in snails is inevitable in parasitic life cycle, therefore it is the key element for preventing the Digenetic Trematode caused diseases. Further research and better understanding is required for minimising the global influence of snail bearing diseases and for securing a better future in the third world countries.