Antidementia and learning/memory function-improving drug

摘要

Provided is an antidementia drug that has a high safety and is free of the problem of side effects. Also provided is a learning/memory function-improving drug that is useful in improving the learning/memory function and can be continuously taken. The antidementia drug and the learning/memory function-improving drug contain, as an active ingredient, a cyclic dipeptide having a 2,5-diketopiperazine structure.