A response to a drug which may be related to the amount received (i.e. the dose). Sometimes Clinical trials are research studies involving people who use healthcare services. They often compare a new or different treatment with the best treatment currently available. This is to test whether the new or different treatment is safe, effective and any better than what is currently used. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. More are done to test the effect of different dosages of the same drug. This may be true for both benefits and harms.