Could cannabis prevent some diseases and conditions in addition to providing symptomatic relief? The preliminary evidence seems to support this idea. Vincenzo Di Marzo, the noted Italian scientist, has stated that cannabinoids help us relax, eat, rest, forget, and protect ourselves.210 Judicious application of phytocannabinoids may augment this process. It has been demonstrated that drugs that are antagonistic to cannabinoid receptors can cause numerous adverse effects, so it could be possible that drugs that play nicely with these receptors may support good health.

Dr. Donald Tashkin’s long-term study of cannabis smokers indicates a small reduction in head, neck, and lung cancers among cannabis smokers that did not also use tobacco. Long-term cannabis users had 3.7 percent lower incidence of lung cancer than nonsmokers.211 A 2013 study showed that cannabis users had lower resting insulin levels and waist measurements than nonusers.212 Cell studies and animal models have shown that cannabinoids such as CBD may arrest and even prevent the occurrence of some tumors.213 Ethan B. Russo’s proposed clinical endocannabinoid deficiency might be treated with small doses of phytocannabinoids as prophylaxis.214 Cannabinoids are also multi-target drugs that may be of interest in preventing complex diseases such as Alzheimer’s.215 Clint Werner, in his book Marijuana: Gateway to Health, suggests that the National Football League may someday wish to consider using cannabinoids such as CBD to protect its players from the effects of violent collisions that can cause cumulative brain injury.216