Agents currently in use against human immunodeficiency virus (HIV) infection, including the prospects of a vaccine, have focused primarily on destroying or disabling the virus. This strategy is hampered by the ephemeral nature of the viral genome. Lithium salts are widely used in psychiatry as mood-stabilizing agents. Studies have revealed, however, that the lithium ion also has significant granulopoietic actions, as well as regulatory effects on select cytokines that enable it to boost the body's natural defense against viral infections, specifically DNA viruses. Moreover, case reports in acquired immunodeficiency syndrome (AIDS) patients, as well as animal studies using related immunodeficiency viruses, provide support for a novel therapeutic role for lithium salts in the treatment of HIV infection. Furthermore, recent studies have revealed an important additional benefit of the lithium ion. In both in vitro and human studies, lithium has been found to increase the synthesis of neuroprotective proteins and to exert possible neurotrophic effects in the human brain. These properties hold great promise in the treatment of AIDS-related neurological deficits such as dementia. This paper reviews the mechanisms involved in and the clinical promise for lithium salts in the treatment of AIDS and AIDS-related dementia.