Animal studies have shown that drugs acting as agonists at alpha-type peroxisome proliferator-activated receptors (PPARα) suppress nicotine self-administration, attenuate relapse to nicotine-seeking behavior in the reinstatement model, and block nicotine-induced neuronal firing and dopamine release in reward pathways of the brain. These results have been demonstrated with synthetic PPARα agonists and with fibrate drugs (clofibrate, fenofibrate), which are used clinically to treat elevated cholesterol and triglycerides levels. Thus, PPARα is a potential target for the treatment of tobacco addiction. This is the first human study to investigate whether a fibrate drug (gemfibrozil, Lopid®) can reduce nicotine reward and aid smokers in becoming tobacco abstinent.