LINKOver the past two decades, numerous clinical trials have been conducted on drugs for treating MS-related fatigue. Of these agents, amantadine has been studied for the longest period, and has shown efficacy in about one third of patients with MS-related fatigue on several commonly used scales. Two randomized -trials of the central nervous system stimulant pemoline have yielded unimpressive results; efficacy was seen at higher doses but coupled with an unacceptable risk of adverse events. The wake-promoting agent modafinil is the only agent to show efficacy compared with placebo on the Fatigue Severity Scale, a measure that is highly resistant to "impulse answering" and is thus viewed as one of the most difficult scales on which to show -benefit. This article reviews fatigue in MS and proposes a rational strategy for evaluation and management of this most common MS symptom.