- noun a trial carried out in a medical laboratory on a person or on tissue from a person
- (written as Clinical Trial)Clinical trials are generally tests of the efficacy of medical and surgical interventions in which an experimental and a control group are compared. With pharmaceuticals, trials go through various phases, identifying safety and efficacy beyond the preclinical trial stage. Trials use samples of patients drawn from a relevant population of patients or people at risk and many are multi-centred and international in nature. They vary greatly in their use of controls (for example, some compare the procedure being studied with a placebo, others with a common practical alternative), and in other aspects of their design, their size, duration, choice of outcome, endpoint.