The problem of interpretation of laws and rules of law is a traditional one for law enforcers. One of the main aspects of the rule of law is the principle of legal certainty, which requires that in the final determination of a case by the courts their rulings must be beyond doubt. "Because the law must be able to follow changing relationships, many laws use terms that are more or less vague and ambiguous. It is the task of jurisprudence to interpret and apply them. In a number of cases, adequate certainty of the law is achieved through judicial interpretation. The aim of the study is to analyse the main legal acts that regulate patients' rights in healthcare organisations. Research Methods. A systematic review of the legislation of the Russian Federation, provisions, existing normative legal acts at the federal and regional levels regulating legal relations in the sphere of health care was carried out. Results. According to the meaning of the positions of the Constitutional Court of the Russian Federation, ambiguity, vagueness, and inconsistencies in regulation are unacceptable, because, preventing proper clarification of its content, open before the law-enforcer the possibility of unlimited discretion, weakening the guarantees of constitutional rights and freedoms. Meanwhile, as the constitutional and judicial practice on entrepreneurial activity shows, the unconstitutionality of the regulation is often caused by the uncertainty of the content of the legal norm. By allowing excessively broad discretion in the process of law enforcement, legal provisions containing such defects violate not only the principles of equality and the rule of law, but also the guarantees of state, including judicial, protection of the rights, freedoms and legitimate interests of business entities. The criteria of accessibility and completeness of information, cover all aspects of a medical intervention, including its risks, possible intervention options, consequences, intended outcomes. With regard to patient's refusal, Article 20(3) of 323-FZ also contains the principle of accessibility of the information provided to the patient's will. That is, the information must be communicated to the patient as fully as possible, without the use of professional terms and professional slang. Besides 323-FZ issues of proper and complete information is contained in legislation on consumer protection, because, according to paragraph 9 of the Resolution of the Plenum of the Supreme Court of the Russian Federation of June 28, 2012 N 17 to the relations on the provision of medical services to citizens is applied legislation on the protection of consumer rights. Conclusion. Undoubtedly, it is advisable to eliminate legal uncertainties. This task is very time-consuming and requires solutions at the legislative, executive and judicial levels. It seems reasonable to eliminate uncertainties by means of the following solutions: 1. Development and implementation at the level of the authorised executive body of imperative informed voluntary consent forms for as many medical interventions as possible, similarly to the legal acts legitimising the VCT form for 14 types of primary medical care. 2. To regulate at the level of official conceptual framework the criteria of accessibility and completeness. 3. To work out the interpretation of qualitative and volumetric information indicators from the standpoint of uniformity and legal certainty principles at the level of the Supreme Court of the Russian Federation. The solution of questions of elimination of legal ambiguities, as applied to the aspect of DIS will allow to significantly reduce legal risks, reduce abuses from patients (patient extremism), improve quality and safety of medical care.