The activities involved in a clinical trial are different for each trial. Before a trial starts, an independent regulatory body looks at the benefits and risks to make sure they are appropriate and makes sure that there is no unnecessary harm or discomfort for participants before it starts.
Once the trial is up and running, but before you enroll, the doctor will clearly explain to you what is involved in the trial and any known side effects of the treatment. These are also always listed in the informed consent document.
Throughout a clinical trial, safety is heavily regulated and monitored. The trial follows a carefully controlled plan which details what researchers will do in the study. As a clinical trial progresses, researchers report the results of the trial at scientific meetings, to medical journals, and to various government agencies.
Any side effects and adverse events that do happen during a clinical trial are recorded. It is required that experimental treatments are evaluated for both immediate and long-term side effects to ensure that researchers are aware of any possible side effects.
If a participant wants to leave clinical trial, they can do so at any time.