The theoretical basis for the occurrence of the right to terminate a contract due to the violation of the expert's obligation to explain and the basis for the obligation to collect information are summarized as follows. In other words, ① There is a continuous contractual relationship between the parties, and the expert knows the purpose of the contract that the other party wants, and the purpose is important for the other party, ② Prior acts by experts (recommendations to the other party or explanations on important matters), ③ The right to terminate a contract may arise due to a violation of the obligation to advise if the purpose of the contract is met due to the neglect of the obligation to explain the main contents. Next, in contracts with experts such as financial product investment or medical care, customer trust becomes the basic premise. Thus, for example, financial instrument experts are obliged to protect customers who have significant gaps in their ability to collect and accumulate information about financial instruments. The basis for this obligation is based on a special personal trust relationship between the parties. Experts are obligated not to infringe on the customer's property and physical integrity interests, and in order to fulfill this obligation, they are actively obligated to obtain and provide information to prevent the customer's interests from being violated. On the other hand, the above legal principles can also be applied to medical contract problems. In the case where the right to terminate a contract arises as an effect of the doctor's violation of the duty of explanation, first, ① there is a continuous contract relationship between the doctor and the patient for a certain period of time, and the patient must have trusted the doctor. The doctor was aware of the patient's wishes for treatment, etc., and the patient's wishes are important for the patient, ② The right to terminate a medical contract should be considered to arise when the doctor did not explain important matters, and ③ the requirement that the purpose of the contract, which is in the best interest of the patient, would not have been achieved due to the neglect of this explanation. Second, doctors are also obligated to collect information at certain times for the best interests of patients. In other words, doctors are obligated to acquire medical knowledge so that they can always be recognized as doing their best in light of the medical level at the time, as well as collecting information such as patients' interests and preferences in the best interests of patients.