Provided is a kampo medicine for treating multimorbidity of Alzheimer-type dementia or mild cognitive impairment and at least one disease from the group consisting of overactive bladder, constipation, and chronic kidney disease with one drug. A kampo medicine for treating multimorbidity with one drug, comprising a drug combination of orengedokuto and ryokeijutsukanto as an active ingredient, wherein the kampo medicine improves a cognitive function in Alzheimer-type dementia or mild cognitive impairment and relieves and treats at least one disease from overactive bladder, constipation, and chronic kidney disease complicated by Alzheimer-type dementia or mild cognitive impairment at a high rate with one drug.