To obtain a neurocyte hyperstimulation inhibitor high in safety as a pharmaceutical, and to provide a highly safe method for inhibiting neurocyte hyperstimulation.

The neurocyte hyperstimulation inhibitor comprises as active ingredients a mixture of a muscarinic acetylcholine receptor agonist (acetylcholine or carbachol) and a type-1 metabolic glutamic acid receptor agonist (e.g. (RS)-3,5-dihydroxyphenylglycine (DHPG)), wherein the amounts of the two active ingredients are less than the corresponding minimum amounts thereof determined as both pharmacologically and pharmaceutically effective as neurocyte hyperstimulation inhibitors singly.