The study will include subjects with peripheral neuropathy caused either by HIV-disease or antiretroviral medication for the treatment of HIV. A neurologist will conduct a neurological and pain evaluation to determine eligibility for the study. Subjects who meet all eligibility criteria will be admitted to the General Clinical Research Center at San Francisco General Hospital for seven days. Subjects will be randomized (like a toss of a coin) to smoke marijuana or a placebo (cigarettes with no THC).