Deanol, a putative acetylcholine precursor, has been used as a treatment for childhood hyperactivity for years. Efficacy has not been satisfactorily established, however. Seventy-four children referred for problems with learning, including many with hyperactivity, were screened for neurological or psychiatric illness, then given deanol, methylphenidate, or placebo in a double-blind fashion for 3 months. Maintenance dose for methylphenidate was 40 mg daily; for deanol, 500 mg. Behavior rating forms, reaction time, and a series of standard psychometric tests were given before and after treatment. Both drugs showed significant improvement on a number of tests; the pattern and degree of change differed slightly for the two. In this paradigm, deanol thus appeared to improve performance in children with learning and behavior disorders. The mechanism of action remains speculative; proof that deanol increases acetylcholine is scanty, and there is a theoretical basis for actually assuming an anticholinergic effect. Further clinical studies on deanol are indicated.