This book emphasis on the piscicidal activities of Cestrum species (Family: Solanaceae). Initial chapters deal with the taxonomical and phytochemical isolation and related topics; here procedures for extraction of various forms of piscicidal principle have been elaborated. Subsequent chapters deals with the toxicological and biochemical investigation to find out the exact cause and mode of fish poisoning. Detail methodology for estimation of various biochemical parameters from various tissues is given in chapters. Finally results are presented in comparative way as well as discussed with findings of other investigators and supported with bibliographic information. To conform the use of this plant piscicide for its commercial use, here investigations are made to find out the possible damage in the nutrients like proteins, lipids and glycogens of the poisoned fish Cyprinus carpio. In fisheries where use of hazardous chemicals is banned, fisherman can use extract of these plants safely. This book is important for the researchers in the field of photochemistry, biochemistry and fishery sciences.