One of the important issues in the field of medical ethics is the patient's consent to treatment. This issue has also been addressed in the law, and Islamic legislators have clarified the conditions of gaining patient's consent and approached questions such as legitimacy of treatments or surgical operations, capacity of the person giving consent and so on. In medical ethics, there are different types of consent including expressed, implied and informed consent, while the Islamic Criminal Act concerns itself only with the expression of consent and it is unclear which type of consent the legislators are referring to. The importance of this issue lies in the fact that gaining the patient's consent without meeting the specified legal conditions causes liability for the physician. This article attempts to clarify the legal conditions for gaining patient's consent and at the same time answer questions such as whether the consent mentioned in the Islamic Criminal Act includes various types in medical ethics or not, how failure to meet the legal conditions for gaining consent should be penalized, what the liabilities are in the event that the patient's consent is not gained, and other questions related to the issue