Introduction. The use of words, mimics and the promotion of the properties of some drugs have a considerable effect in medicine. Every doctor has this tool at his disposal. Patients are very receptive to both positive and negative suggestions. These reactions are emphasized in critical situations, such as the pre-operative period, serious illness or accident. Thus, being aware of the importance of these effects, we realize the need to correlate with the bioethics principles. Aim of the study. To reveal the bioethical aspects of the placebo effect in the contemporary medical act.  Materials and methods. The study has used published scientific research, sociological studies and statistical data. Bioethical and sociological methods have been applied. Results. Following the placebo treatment, due to positive thinking and trust in the doctor, not only the patient's mood changes, but also obvious psychosomatic effectsare noticed, thus facilitating the medical act optimization.  At the same time, the nocebo side effect occurs when the patient feels worse after the doctor's wrong counseling and receiving a real or false pill, and not trusting in the therapy. The power of thought and trust in medical staff works, as well as reversely. As a result of the researches, the force of the negative suggestion is much higher than the positive suggestion, namely 90% versus 50%.  Conclusions. The multilateral, impeccable doctor`s preparation, the knowledge of the bioethical principles and their methodical application in the medical act, provide a more successful coefficient in the practice of the administered treatment.