Sleep disorders are a substantial problem for cancer survivors, with prevalence estimates ranging from 23% to 61%. Although numerous prescription hypnotics are available, few are approved for long-term use or have demonstrated benefit in this circumstance. Hypnotics may have unwanted side effects and are costly, and cancer survivors often wish to avoid prescription drugs. New options with limited side effects are needed. The purpose of this trial was to evaluate the efficacy of a Valerian officinalis supplement for sleep in people with cancer who were undergoing cancer treatment. Participants were randomized to receive 450 mg of valerian-or placebo orally 1 hour before bedtime for 8 weeks. The primary end point was area under the curve (AUC) of the overall Pittsburgh Sleep Quality Index (PSQI). Secondary outcomes included the Functional Outcomes of Sleep Questionnaire, the Brief Fatigue Inventory (BFI), and the Profile of Mood States (POMS). Toxicity was evaluated with both self-reported numeric analogue scale questions and the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. Questionnaires were completed at baseline and at 4 and 8 weeks. A total of 227 patients were randomized into this study between March 19, 2004, and March 9, 2007, with 119 being evaluable for the primary end point. The AUC over the 8 weeks for valerian was 51.4 (SD = 16), while that for placebo was 49.7 (SD = 15), with a P value of 0.6957. A supplemental, exploratory analysis revealed that several fatigue end points, as measured by the BFI and POMS, were significantly better for those taking valerian over placebo. Participants also reported less trouble with sleep and less drowsiness on valerian than placebo. There were no significant differences in toxicities as measured by self-report or the CTCAE except for mild alkaline phosphatase increases, which were slightly more common in the placebo group. This study failed to provide data to support the hypothesis that valerian, 450 mg, at bedtime could improve sleep as measured by the PSQI. However, exploratory analyses revealed improvement in some secondary outcomes, such as fatigue. Further research with valerian exploring physiologic effects in oncology symptom management may be warranted.