That depends on the re-hab, but most will give you Tylenol for aches and pains. Mylanta or an alternative for heartburn. The list is long - but they won't give you anything that is considered "mood altering."
You can't put a time constraint on something so complex. I went to drug rehab once (a short stay) and went right back to my old ways when I got out. It took a long term stay in drug rehab at Palm...
Drug rehabilitation (often drug rehab or just rehab) is a term for the processes of medical and/or psychotherapeutic treatment, for dependency on psychoactive substances such as alcohol, prescription...