The clinical trial is that the end of an extended and careful research and development process (drug/vaccine/medical device). Clinical trials should follow strict step by step process and scientific standards to guard and stop patients from diseases. The first purpose of the clinical test is to form sure that the merchandise is safe, effective and bringing value to the mankind. Conflicts between the goals of science and therefore the got to protect the rights and welfare of human research participants end in the central ethical tension of clinical research. The goal of clinical research is to get scientifically valid data efficiently while protecting research participants. Decisions should favor the rights and welfare of human participants instead of the scientific ends.