Sorry for my late reply.
Drugs only stop that process so we may think we are better but we are not cured.
Yes, I know that already from personal experiences (in case of stopping a fever too soon, it may stretch the disease-full times even longer), for example.
To answer your question: If the dose does not make the poison then there is no over dose which causes damage? To take another example (and not LSD) what about sleeping pills taken in great amounts? It is said that they can cause death. Do you know anything about it?
They say too much of anything can kill you. There is obviously SOME truth in 'the poison is in the dose' but it's not that simple. I think this is where the old 'immune system' story comes in. If you take germs and viruses out of the story and substitute poisons or toxins you will find your answer.