A clinical trial in which two or more doses of an agent (such as a drug) are tested against each other to determine which dose works best and is least harmful. Commonly, a dose ranging trial will include a placebo group of subjects, and some groups that experience different doses of the test drug. For example, a typical dose-ranging trial may incorporate four groups: these groups would be separated into a placebo group, low-dose group, medium-dose group and a high-dose group.

See also:
Efficacy
Risk-benefit analysis
Clinical trial