A case of essential tremor since early adultness is presented, which has been treated successfully with the acetylcholine precursor 2-dimethylaminoethanol (deanol) for 10 years. Development of a marked dyskinesia syndrome affecting predominantly orofacial and respiratory musculature has been noticed with this medication. Partial remission after discontinuation and a favorable response to anticholinergics are suggestive of an adverse drug effect.