Distigmine is widely used for the treatment of dysuria, which is caused by various types of psychotropic medications. Distigmine, however, is also known to induce adverse cholinergic effects, such as diarrhea and salivation, with a decreased level of serum cholinesterase. We evaluated the possibility of using serum acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) as specific clinical markers for the adverse cholinergic effects of distigmine. Of the twelve patients treated with distigmine for dysuria caused by psychotropic drugs six patients presented both adverse cholinergic effects and decreased levels of serum AChE and BChE. The other six presented neither of these changes. This study suggests that the values of serum AChE and BChE may be useful markers for the manifestation of adverse cholinergic effects caused by distigmine.