It has been proposed that the patient's relative ignorance about medicine, 'asymmetry of information between doctor and patient', should place a patient in a disadvantaged position when purchasing medical care. Even if rapidly developing information technologies can enhance the patient's access to health information, a patient doesn't have enough ability to understand, interpret and evaluate it. So, the doctor's effort at sincerely helping patient understand and utilize health information by effective communication with patient might improve the patient's asymmetric information problem and affect the patient's use of medical care by way of its being a source of patient's solid trust on doctor. This research seeks to determine whether a doctor's effort, mentioned earlier can affect the elderly use of medical care. This study used data from a survey sample of people aged more than 65 living in Seoul and Chuncheon, Korea. The results suggest the doctor's effort level has a statistically significant positive effect on the elderly use of medical care, which suggest a doctor's effort of effectively communicating with patient would ameliorate patient's information problem and it could be a source of patient's trust on doctor, so this trust would lead a patient to consume more medical care.