Medications can help clients safely and comfortably withdraw from substances such as alcohol, opiates, or sedatives if they have a physical addiction. The medicines used will depend on the drug or drugs on which they are dependent. Medication-assisted treatment is the use of medications approved by the US Food and Drug Administration, in combination with counseling and behavioral therapies, to provide a whole-client approach to the treatment of opioid, alcohol, or tobacco use disorders. The goals of this chapter are to learn about types of medication that aid recovery from a substance use disorder, to understand the reasons why some people may have problems with medication, to learn about withdrawal symptoms and medications that help, to understand the effects of drug and alcohol use on psychiatric medications, and to determine whether or not a client needs medication to help with his or her substance disorder.