Is marijuana use deadly? Can you overdose on weed? How many cannabis deaths have there been? There are currently over 4 million U.S. citizens using medical cannabis to treat various conditions, ranging from insomnia, anxiety, epilepsy, chronic pain, and much more. Recreational cannabis is also being made legal in a growing number of states throughout America with each passing year, with 36 states that have now legalized the plant. But are there risks with the increased use of cannabis? Can marijuana kill you? Let's find out. What is an overdose? An overdose occurs when the human body receives too much of a substance. Typically, overdoses are caused by alcohol, prescription medications, illegal opioids, methamphetamines, and many other substances. If medical intervention doesn't occur quickly, overdoses can be fatal.