Bit off topic, but this got me thinking. I don't know why, but I'd always just felt that dmt was something you couldn't physically overdose with, or actually harm yourself. Obviously, I'm not talking about damage to your psyche.

Found this paper Psychedelic 5-Methoxy-N,N-dimethyltryptamine: Metabolism, Pharmacokinetics, Drug Interactions, and Pharmacological Actions and it says the LD50 in mice ranges from 48 to 278 mg/kg, depending on administration method.

Made me sad to think of the poor little creatures being purposefully killed with the spice, just to satisfy our curiosity.

As void says, oral administration would seem to preclude the possibility of 'instant' breakthrough.