Unlike other drugs, overdosing on marijuana is not an issue. According to the Drug Enforcement Administration, there have been no reports of marijuana overdose fatalities in the U.S. However, when the source of the marijuana is not known there is always the possibility that it has been cut with another substance that could cause harm or an overdose. If in doubt that someone is suffering from a drug overdose of any kind, always call 911 or get the person to the emergency room immediately.