A main unit of an electronic chart apparatus is connected to a chart database, a medicament information database and a food information database through a LAN. The chart database contains chart data created based on medical records including a diagnosed injury or disease and drugs prescribed for this injury or disease. Based on the medical records on a patient, cautionary information on such foods that can give bad influence on the patient in relation to the diagnosed injury or disease is retrieved from the food information database, and also cautionary information on such foods that must be taken with caution about concomitant intake with the prescribed drugs is retrieved from the medicament information database. With reference to the results of retrieval, a dietary instruction is given to the patient, avoiding such foods that are indicated by the retrieved cautionary information.