I have never done DMT, but people that take it frequently report encounters with "aliens", similar to those of non-drugged people - and this lends credence to the theory that the brain has chemicals that can do this, naturally.

Terrence McKenna's books and tapes are very informative, and he was a great entertainer, but his own brother (who is a first-rate chemist) was very skeptical about Terrence's claims of visiting other dimensions and communicating with non-human beings while on powerful drugs. "Food of the Gods", and "True Hallucinations" are the titles of two of his books that I own. I also have an audio tape. Who knows, maybe he was right. Anyway, it's food for thought - if nothing else.