DOES CANNABIS HAVE A LETHAL HUMAN DOSE?
There has never been a documented human fatality solely from overdosing on tetrahydrocannabinol or cannabis in its natural form. However, numerous reports have suggested an association of cannabis smoking with an increased risk of myocardial infarction. Information about the toxicity of THC is primarily based on results from animal studies. The toxicity depends on the route of administration and the laboratory animal.
The estimated lethal dose of intravenous dronabinol (also known as Marinol) is 30 mg/kg, meaning lethality is unlikely. The typical dosage administered is two 2.5 mg capsules daily; for an 80 kg man (~170 lb) to die from a THC overdose, this would translate to 960 capsules infused intravenously to achieve this high a dose. Non-fatal overdoses have occurred: "Significant CNS symptoms in antiemetic studies followed oral doses of 0.4 mg/kg (28 mg/70 kg) of dronabinol capsules."
Its status as an illegal drug in most countries can make research difficult; for instance in the United States where the National Institute on Drug Abuse was the only legal source of cannabis for researchers until it recently became legalized in Colorado and Washington.
SOURCE for full article:Wikipedia