The authors assessed the efficacy, tolerability, and safety of divalproex sodium for the treatment of agitation associated with dementia in a 6-week, randomized study of 56 nursing home patients with agitation and dementia treated with either placebo or individualized doses of divalproex sodium. Participants were blinded to treatment except for a physician-monitor and a pharmacist. When several covariates were taken into account, the drug/placebo difference in Brief Psychiatric Rating Scale Agitation scores became statistically significant (P=0.05). Sixty-eight percent of patients on divalproex were rated as showing reduced agitation on the Clinical Global Impression scale, vs. 52% on placebo (P=0.06 in the adjusted analysis). Side effects occurred in 68% of the divalproex group vs. 33% of the placebo group (P=0.03) and were generally rated as mild. This placebo-controlled study, despite some limitations, suggests possible short-term efficacy, tolerability, and safety of divalproex for agitation in dementia and supports further placebo-controlled studies.