Physiologica Tolerance - Is Alcohol a Toxic Drug?

There are some substances, like marawuana, that don't appear to develop the same kind of physiologic tolerance and withdrawal. So how do we sort of know this, or what's the argument for this? The first is that our gaberos heptors get regulated so heavily that if you're addicted to alcohol, and you stop cold turkey, the withdrawal that you go through can conceivably be fatal. Or not conceivably, it really can be fatal, and is fatal for unfortunate presentage of people.