AbstractThiol‐containing compounds pose bioanalytical challenge in several dimensions due to extreme reactivity of the sulfhydryl group. The development of robust bioanalytical methodology for thiol groups should address the aspects of adequate stabilization in the biological matrix and selectivity considerations. In this context, availability of plethora of thiol reagents provides ample opportunity to achieve the above goals. However, several considerations need to be factored into the decision‐making of a suitable scheme for the thiol drugs under investigation. This review provides some critical insights to many such considerations that may be vital for development and validation of methods for thiol‐containing drugs. Copyright © 2003 John Wiley & Sons, Ltd.