Introduction: The once accepted view that having medical knowledge and skills is a sufficient guarantee that the final decision on treatment in the best interest of the patient will be correct, requires both scientific and professional assessment nowadays, because each medical assessment contains a set of values or norms beyond medical values. Procedures: The data used for writing the dissertation were collected by searching online databases. Both articles in Croatian and English were used. Discussion: Medical competence is no longer the only competence that leads to a medically correct decision, as all medical decisions contain both medical technical and moral components. Bioethics, as a multidisciplinary science, provides healthcare professionals, patients and all others involved in decision-making with an adequate framework for making the right medical and ethical decisions. Bioethics is defined as "an interdisciplinary science that governs human behaviour in the field of life and health in the light of moral rational values and principles, as well as their legal and social standardization." It is based on the book “Principles of Biomedical Ethics” written by Tom L. Beauchamp and James Childress in the mid-1970s. There are four basic principles of biomedical ethics: the principle of respect for autonomy, the principle of beneficence, the principle of non-maleficence, and the principle of justice. The principles apply to all patients regardless of their race, gender, religion, or political affiliation. Although the Hippocratic Oath states Primum non nocere - do no harm in the first place, throughout history many medical experiments have been conducted in which these basic principles have been significantly violated. After the trial in Nuremberg, where the cruellest experiments were discovered, attention began to be paid to the regulation of research on humans, consequently, in 1949 the Nuremberg Code was adopted. Conclusion: With the development of science, a need to renew and amend the Nuremberg Code appeared, which resulted in the adoption of the 1964 Declaration of Helsinki. Both documents focus on informed consent and emphasize that human medical research should prioritize the protection of research participants over the interests of science and society.