To the Editor: Tacrine, a reversible cholinesterase inhibitor active in both the central and peripheral nervous system, is indicated for the treatment of Alzheimer’s disease. Because its peripheral cholinergic activity causes gastrointestinal side effects, including cramping, nausea, vomiting, and diarrhea, only a minority of patients treated with tacrine can tolerate the recommended daily dose of 40 mg q.i.d. We have been able to overcome these problems in four patients with the adjunctive use of propantheline, a peripherally acting anticholinergic medication (1).