Cannabis 101:

Scientists are only recently beginning to understand the many complex ways that cannabinoids interact with the human body. Subjects experience psychological and physiological effects after ingesting cannabis because cannabinoids, THC in particular, interact with a complex and dense receptor system within the body.

The CB1 receptors, first identified in the late 1980s, reside predominantly in the nervous system and their stimulation is responsible for the plant's psychoactive and behavioral effects, among other functions. The CB2 receptors, identified in the early 1990s, reside primarily in the immune system and are involved in the moderation of a number of biological functions, including inflammation and pain response. Naturally occurring chemicals in human body (called endocannabinoids), which possess a similar molecular structure to herbal cannabinoids, act as neuromodulators and cytokine modulators within this receptor system to regulate many of the body's essential physiological functions -- including appetite, blood pressure, reproduction, bone growth, tumor modulation, immunity, inflammation, pain sensation, memory, and muscle tone, among others.

It is theorized that a properly functioning endogenous cannabinoid receptor system is necessary for good health and that certain disease types may be the result of deficiencies within this system. According to a National Institutes of Health review, "Modulating the activity of the endocannabinoid system ... holds therapeutic promise in a wide range of disparate diseases and pathological conditions, ranging from mood and anxiety disorders, movement disorders such as Parkinson's and Huntington's disease, neuropathic pain, multiple sclerosis and spinal cord injury, to cancer, atherosclerosis, myocardial infarction, stroke, hyper- tension, glaucoma, obesity/metabolic syndrome, and osteoporosis, to name just a few.