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:
- NHS Clinical Trials
- Molecules to medicine: Clinical trials for beginners guest blog series on Scientific American
- ClinicalTrials.gov
- FDA (US Food & Drug Administration)
Last updated:
12 Oct 2011 
