They say that it isn't possible to overdose on marijuana and die, and there really have been no confirmed cases of this happening. But that does NOT mean that pot can't kill you! 

A 19-year-old student, Levy Thamba, at Northwest College in Powell, Wyoming who was visiting Denver on spring break, fell from a balcony at the Holiday Inn Denver East and died after eating a weed-infused cookie.

The Denver coroner said Thamba's death was caused by "multiple injuries due to a fall from height," but also listed "marijuana intoxication" from marijuana-infused cookies as a significant condition contributing to the death. The coroner's office also said Thamba had no known physical or mental-health issues, and toxicology tests for other drugs or alcohol came back negative.
There is currently no law on how much THC can be in marijuana edibles, but the threshold for a driving under the influence of marijuana violation is 5 nanograms of THC per milliliter of blood. Thamba's marijuana intoxication level was 7.2 nanograms of THC per milliliter.