There are many reasons for wanting to understand what science has so far revealed—and what remains unknown—about marijuana's medical potential. Can marijuana really help people with AIDS (acquired immune deficiency syndrome), cancer, glaucoma, multiple sclerosis, or any of several other conditions it is purported to relieve? How does marijuana affect the human body? Could the potential benefits of legalizing marijuana for medicinal use possibly outweigh the risk of encouraging drug abuse? All of these questions remain to be answered completely, but over the past two decades scientists have made significant progress in revealing how chemicals in marijuana act on the body. Researchers have also studied how marijuana use affects individuals and society as a whole.

Unfortunately, much of what scientists have learned about the medical use of marijuana has been obscured by highly polarized debate over the drug's legal status. At times advocates for medical marijuana have appeared to be discussing a different drug than their opponents. Consider the following statements:

There are over ten thousand documented studies available that confirm the harmful physical and psychological effects of . . . marijuana.

—from the California Narcotic Officers' Association

Marijuana is NOT a Medicine, Santa Clarita, CA (1996), p. 2.