Abstract: For clinical trials, efficacy evaluation of new drugs might not be reliable if it is based on positive drugs for comparison. Furthermore, the clinical trial itself might encounter general ethical problems. When proposing clinical trials for new drugs, placebo drugs should be chosen for comparison during Phase II. In view of research objective and disease situation, patients with mild conditions should be chosen for clinical trials. On the basis of effectiveness of the new drugs, second stage of Phase II and Phase III can be arranged. Add-on research methodology can be adopted in the second stage of Phase II to adequately extend indication. Phase III clinical trials can choose placebo or suitable positive drugs for comparison. This will ensure the effectiveness of the new drugs as well as meet the ethical requirements.

Key words: Therapeutic effect, Ethics, Clinical trials, Design