Not at all. Asking that question is like saying "can you
overdose on meditation and dreaming?" DMT has NO negative side
affects (provided you take it correctly), and often can change your
life for the btter.
the only damage that it does is to your lungs (because you smoke
it). All living things have it, and it is produced when we sleep,
and are dying. It is also produced in mass quantities in
meditation. In no way is it dangerous. To counter the lung problem,
use a vaporizer.
You can overdose on anything... Substances that naturally occur
in the human body can mess you up more than substances that do not
naturally occur in the body.