What is a clinical trial?

A clinical trial is a research study in human volunteers to answer specific health questions.

Clinical trials are carried out in four phases:

  • Phase I and Phase II trials check on safety – they make sure the treatment does no harm to patients. 
  • Phase III or IV trials focus on assessing how effective the treatment is, and developing it into a therapy that can be made widely available.
For more detailed information about the clinical trials process, visit these websites, or read our graphic short story, Hope Beyond Hype (detail pictured right).
Last updated: 
12 Oct 2011