They say that the THC in marijuana causes tumor cells to begin to degrade themselves from the inside (a process called autophagy, i.e. "self-eating"). Although autophagy has been shown to promote cell survival in some cases and cell death in others, the authors show that in this case it causes cancer cells to undergo programmed cell death (apoptosis). Thus, THC activates a series of events within cancer cells, inhibiting tumor growth.
Marijuana has been shown to be effective in reducing the nausea induced by cancer chemotherapy, stimulating appetite in AIDS patients, and reducing intraocular pressure in people with glaucoma. There is also appreciable evidence that marijuana reduces muscle spasticity in patients with neurological disorders. A synthetic capsule is available by prescription, but it is not as effective as smoked marijuana for many patients. Pure THC may also produce more unpleasant psychoactive side effects than smoked marijuana. Many people use marijuana as a medicine today, despite its illegality. In doing so, they risk arrest and imprisonment.