Every medical intervention to the patient without disclosing the diagnosis, treatment process, risks and alternative treatment options is illegal. In order to make the intervention legal, the doctor must disclose the patient clearly and in an understandable language. Accordingly, doctor may use different standards such as the professional practice standard, the reasonable patient standard and the subjective standard when fulfilling his disclosure requirement to the patient. However, one should bear in mind that, there are some circumstances which exempts the doctor from disclosure requirement; immediate medical responses, patient's waiver from his illumination right, patient's knowledge about the intervention and in case of negative effects of disclosure to the patient. It should be kept in mind that, burden of proof in disclosing the patient is on the shoulders of the doctor.