Can subjects voluntarily withdraw from clinical trials?

According to the tenets of the declaration of Helsinki, subjects can withdraw from the trial at any time according to their own wishes without any reason. However, because the reasons for withdrawal may affect the evaluation of the efficacy and safety of trial drugs, it is best to persuade subjects to conduct the final evaluation to clarify the reasons for withdrawal and record them in the case report form. When the investigator believes that it is not beneficial for the patient to continue to participate in the trial, the trial treatment of a subject can be terminated. In fact, some subjects could not be followed up on schedule, could not take medicine as required, and had poor compliance with the trial treatment. When the investigator terminates a patient to continue participating in the trial, the reason should be recorded in the case report form in detail. The trial plan should describe the steps of how to follow up the subjects who were terminated or voluntarily withdrew from the trial.