You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Healthy volunteers are recruited in which phase of clinical trials? and explain in detail?
Phase 1- Done on healthy people. Maximum tolerable dose of drug is tested Phase 2- Done on fewer patients (20-200) . Efficacy and safety of drug is tested here Phase 3-Done on more patients ( upto 5000).Efficacy is confirmed in this phase Phase 4- Post marketing surveillance. Long term and rare side effects are monitored in this phase