Evidence for dietary/nutritional treatments of attention-deficit/hyperactivity disorder (ADHD) varies widely, from double-blind, placebo-controlled trials to anecdotal. In guiding patients, clinicians can apply the SECS versus RUDE rule: treatments that are Safe, Easy, Cheap, and Sensible (SECS) require less evidence than those that are Risky, Unrealistic, Difficult, or Expensive (RUDE). Two nutritional treatments appear worth general consideration: Recommended Daily Allowance/Reference Daily Intake multivitamin/mineral supplements as a pediatric health intervention not specific to ADHD and essential fatty acids, especially a mix of eicosapentaenoic acid, docosahexaenoic acid, and γ-linolenic acid as an ADHD-specific intervention. Controlled studies support the elimination of artificial food dyes to reduce ADHD symptoms, but this treatment may be more applicable to the general pediatric population than to children with diagnosed ADHD. Mineral supplementation is indicated for those with documented deficiencies but is not supported for others with ADHD. Carnitine may have a role for inattention, but the evidence is limited. Dimethylaminoethanol probably has a small effect. Herbs, although "natural," are actually crude drugs, which along with homeopathic treatments have little evidence of efficacy. Consequences of delayed proven treatments need consideration in the risk-benefit assessment of dietary/nutritional treatments.