If you need to detox from drugs and alcohol then you might need a detoxification drug to help you through this.  In some cases, withdrawal from certain drugs or from alcohol can be dangerous so you might need medication in order to help you through it. If that is the case then what you really need is a medically supervised detox, not to simply get the medication on your own and try to detox yourself.  The reason for this is because addicts and alcoholics are notoriously bad at medicating themselves, especially if they are attempting to quit using their drug of choice at the time.

The drugs that they give you at rehab in order to help you detox will depend on what drugs you are coming off of.  If you are an alcoholic then they will give you a pill that stops you from shaking so much and helps prevent seizures.  If you are addicted to opiates or heroin then they will give you a synthetic partial opiate like Suboxone in order to help treat your withdrawal symptoms.  If you are coming off of other drugs such as marijuana or cocaine then they will likely not give you any medication to help you with that, because the withdrawal is not very physical in those cases.

Being in drug treatment has other benefits as well that go far beyond the pills that they give you in detox.  For example, after you leave the detox area you will likely go into residential treatment, where you will learn more about how to live a clean and sober life when you leave rehab.  You will also probably be introduced to groups and meetings and sort of see how the process of networking can work for you in early recovery.

Now if you are actually interested in cleansing your body out instead of detoxing from drugs and alcohol, then you probably do not need a pill or any supplements to do this.  Instead you need to approach this sort of detox from a fitness and nutritional standpoint.  One way to detox your body without drugs is to do a juice fast for a few days.  The idea is simple: consume nothing but juice and water for 3 days, no pulp allowed.  This will cleanse your body much deeper than buying any pills or detox drugs will do for you.  If  you continue to do juice fasts every few months then you will see that your body becomes more and more cleansed over time.