Detox is short for detoxification. Rehab is slang for rehabilitation. Detox occurs in days or weeks while rehab typically lasts for months. Medical or supervised detox is the process of getting the drugs or alcohol out of your system safely. It may be in a hospital, but usually is in a different facility and can even occur at home. Rehab can be in a residential facility, but can also be in an outpatient setting where you attend daily counseling or group sessions, but then live at home.