Dogs and people have been interacting with each other from the very beginning. Wolves and wild dogs eventually domesticated themselves and became increasingly involved in people's daily lives. In time, from the escorts in the hunt and the guards, they became man's best friend. Throughout history, many scientists have begun to perceive the positive effect of animals, including dogs, on human mental and physical health. Thus, the development of associations engaged in the selection, education and integration of dogs for therapeutic purposes and development of the therapeutic dog has also occurred. The therapeutic dog has found its role in many areas. The work lists the most common conditions and diseases in which the therapeutic dog can improve the condition of the user. The therapeutic dog has a positive effect on physiological conditions such as lowering blood pressure and heart rate, reducing pain, anxiety, depression and generally positively acts to strengthen the immune system, and thus to reduce the disease. In addition, therapeutic dogs have proved to be good intermediaries in perfecting communication skills, increasing social integration, verbal communication and self-esteem of users. Positive influences have also been reported in behavioural problems and are therefore used in emotional disorders and autism. Therapeutic dog does not necessarily have to be a dog of a certain breed, but it is essential that it possesses a certain empathy, that it is not aggressive or fearful to humans and other animals and that it is stable in character. Therefore, all therapeutic dogs undergo training, after which they receive a certificate that allows them to work in terms of therapeutic dog. In addition to the benefits of users, it is always necessary to take care of the welfare of the therapeutic dog.