In a medical information processing device, method, and program, assistance for the work for checking the symptoms of a chronic disease from the inspection data or medical information of a subject patient is provided. A plurality of dosage details are acquired in which information specifying a drug administered to a subject patient, the amount of drug, and the dosing date of the drug are associated with each other. Based on the plurality of acquired dosage details, a dosing period equal to or longer than a predetermined period is identified among dosing periods of the drug for which it is regarded that both information specifying the drug and the amount of drug are the same. The identified dosing period is specified as a dosage details common period, and a period excluding a predetermined initial or final period from the specified dosage details common period is determined as a stable dosing period (Tc).
