Smoked cannabis was superior to oral synthetic THC as well as the conventional agents available. A Legal, Historical, and Pharmacological Overview of the Therapeutic Use of Marijuana , 1997. Forty-four percent of oncologists said that they had suggested that a patient smoke cannabis for relief of the nausea induced by chemotherapy. The medical safety of marijuana is great. It does not kill people in overdose or produce other symptoms of obvious toxicity.
Occasional use is no more of a health problem than the occasional use of alcohol.