It is well known that praziquantel (PZQ) has contributed a lot and still contributing to control and prevent schistosomiasis and it is the only drug available for schistosomiasis. It has also the following important features: good efficacy, safety, operational convenience and low cost. However, exclusive use of it for controlling the disease has many limitations. For instance it does not prevent re-infection. Not only this but due to usage of the drug for more than three decades we may face emergence of drug resistance in a near future if we do not avoid exclusive use of it as the only option to control the disease. The other drawbacks of PZQ are: Its lack of activity against immature schistosome, a potential to give unsatisfactory
