Comparing with chemical assay and physical assay, bioassay is less elaborate, less accurate, more troublesome, more laborious and more expensive. But, it is the only assay to be done if an active principle of drug is unknown and if it is hard to isolate. Chemical method is very complex method which requires high chemical dosage and chemical composition shows the pharmacological actions against the drug. Other purpose of bioassay is to standardize the preparation so that each contains the uniform specified pharmacological activity. In this way, it serves as a pointer in the Commercial Production of drugs when chemical assays are not available or do not suffice. From the clinical point of view, bioassay may help in the diagnosis of various conditions.