Good Clinical Practice (GCP) is an international quality standard that provides protection for human subjects in clinical trials. It outlines ethical and scientific standards for trial design, conduct, and reporting. The key principles of GCP are that clinical trials must be justified based on prior evidence; subject well-being must be prioritized over scientific objectives; and trials require oversight from ethics committees and qualified investigators. GCP aims to ensure clinical trial data are credible and that subjects' rights and safety are protected.