BACKGROUND This article continues our medicolegal series that addresses issues affecting current dermatology practice. Informed consent and informed refusal have become cornerstones of modern American healthcare, and can serve to facilitate communication and trust between physician and patient. METHODS A format with an initial discussion of legal concepts is followed by hypothetical problems and a review of actual cases to illustrate the principles of informed consent and informed refusal. RESULTS A valid informed consent from a competent patient should be obtained before initiating most dermatologic treatment. When a competent patient refuses a recommended medical test or procedure, the physician should make sure the patient understands the potential negative consequences of refusal. Some form of written documentation in the medical record is advised in either situation. CONCLUSIONS Failure to obtain a patient's informed consent prior to beginning treatment or failing to obtain an informed refusal before accepting a patient's decision to forego a test or procedure may subject the dermatologist to multiple later allegations, most commonly negligence.