Cannabis Sciences: the study of a drug derived from the family of plants that includes hemp. Cannabis can be smoked or eaten. Use of cannabis produces a mild sense of euphoria, as well as impairments in judgment and lengthened response time. Although cannabis use is illegal in most parts of the world, the plant appears to have some potential for medical use, particularly as a palliative for glaucoma and disease-related loss of appetite and wasting, as is often seen in cancer, AIDS, and other illnesses. In some areas of the US, individuals whose physicians recommend the medical use of cannabis can obtain special permission.