juana]. Two puffs and my husband would go for chemotherapy with a smile and come home happy. He didn't [need to smoke it] again until the next day.

This man died of his cancer but, according to his wife, using marijuana —a drug he would never have tried otherwise—made his last months bearable.

People with cancer who use marijuana say that it benefits them in several ways: by quelling nausea, suppressing vomiting, increasing appetite, relieving pain, and soothing anxiety. Clinical studies indicate that marijuana does none of these things as well as the best medications available, but marijuana has the apparent advantage of treating several symptoms simultaneously. Medicines based on certain chemicals in marijuana could also be used to complement standard medications or to treat patients for whom such therapies have failed.

Considerable clinical evidence indicates that marijuana could yield a variety of useful medicines, especially for nausea, vomiting, and appetite stimulation. THC, in the form of Marinol (dronabinol), has already been used for more than a decade to treat these symptoms in cancer patients and for several years in AIDS patients as well. But other cannabinoids, or combinations of cannabinoids, may prove to be more effective than THC alone. If so, any pharmaceuticals that result from such discoveries could benefit people with AIDS as well as those living with cancer.

Nausea and vomiting occur when one of several sensory centers, which are located in the brain and the digestive tract, becomes stimulated (see Figure 6.1). It is possible to become nauseous without vomiting or to vomit without feeling nauseous beforehand. Vomiting (also called emesis) involves a complex co-ordination of the digestive tract, respiratory muscles, and posture. Because all of these actions can be readily measured, scientists have been able to reconstruct the chain of physiological events that lead to vomiting.

Conversely, little is known about the actual mechanisms that trigger nausea, which appears to result from brain activity alone.