A comprehensive document summarizing preclinical and clinical data relevant to the use of an investigational product (test drug) in human subjects.

The IB is of critical importance throughout drug development and is continually updated. It provides the rationale for the planned use of an investigational product in a trial (such as dose and route of administration) and plans for participant monitoring and care. It is of particular importance for ensuring that investigators carrying out clinical studies can assess the risks and benefits associated with a new investigational drug and can deliver appropriate care to those who receive it.

Maintenance of the IB is an aspect of Good Clinical Practice and is covered by International Council for Harmonization (ICH) and other guidelines.