MedicalTerminology DB
General Medical Terms

phase III trial

Meaning of phase III trial: A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects).

Definition of phase III trial

A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people.

Written and maintained by James Murray Last updated July 21, 2026 Educational reference, not medical advice. Read the limitations.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.