We examined in a double-blind, placebo-controlled study the effects of botulinum toxin in 10 patients with essential head tremor. Each subject received two treatments approximately 3 months apart, one with botulinum toxin injections and another with normal saline injections into the sternocleidomastoid and splenius capitis muscles. The subjects were assessed before each treatment and at 2, 4, and 8 weeks after injections. There was moderate to marked improvement in clinical ratings in five subjects after botulinum toxin injections and in one subject after placebo. There was moderate to marked subjective improvement in five patients with botulinum toxin as compared with three subjects with placebo. Side effects were mild and transient. We conclude that botulinum toxin may be useful for patients with essential head tremor who have failed to benefit from oral medications.