The primary goal of psychotherapy is to help others with the suffering they are experiencing. Naturally, most publications are geared toward ways to help in the best possible, professional way. Relatively little attention is paid to the impact of the helping process on the therapist himself and this can be manifold. It is possible to experience positive personal changes like vicarious resilience or vicarious post-traumatic growth. There are few publications in Polish on the potentially negative effects on the therapist: compassion fatigue; professional burnout; secondary traumatic stress, or vicarious trauma. In this publication, the author discusses the potentially negative consequences of therapy provision for the therapist focusing in particular on vicarious trauma, which can affect many therapists working with traumatized individuals. He outlines the processes in the therapist’s mind of confronting his own beliefs about the world and needs for trust, security, independence, respect for others, a sense of power and efficacy, and the search for a frame of reference for experiences — with what his patients experience. The author also discusses the processes occurring in the therapist's brain during therapy in the mirror neuron system, the amygdala body, the autonomic system and the hypothalamic-pituitary-adrenal axis. Awareness of these changes can be a prelude to controlling and limiting their impact on the therapist.