Can you overdose on cannabis? What is the lethal dose?

A fatal overdose from cannabis alone has never been documented in humans. The estimated lethal dose of THC in humans (extrapolated from animal data) is approximately 1,260mg/kg body weight — for a 70kg adult, this would be roughly 88 grams of pure THC, an amount impossible to consume in a single session. However, "overdose" in the clinical sense (requiring medical attention) does occur. Cannabis overconsumption causes cannabinoid hyperemesis syndrome, severe anxiety and panic attacks, psychosis-like episodes, tachycardia, and in rare cases, cannabis-induced psychosis requiring hospitalization. Edibles are the most common cause of overconsumption due to delayed onset. Synthetic cannabinoids ("spice," "K2") are far more dangerous and have caused deaths. Cannabis use is also associated with increased accident risk (driving, falls) and cardiovascular events in susceptible individuals.