A complication of the opioid-based treatment of pain in patients with a cancer could be opioid-induced hyperalgesia. This phenomenon is paradoxical occurrence of pain or exacerbation of pain during the use of opioid analgetics. Opioid-induced hyperalgesia is associated with changes in the conformation of the opioid receptors. In this paper based on the literature presens 6 mechanisms of this phenomenon. These are: stimulation of NMDA receptors, opioid receptors desensitization, the effect of dynorphin A, descending impulse control pain associated with activation of On-Off cells, increasing the level of cAMP and genetic changes involving the substitution of methionine by valine affecting neurotransmission of dopamine/norepinephrine. In the following section describes the proposed method of treatment of opioid-induced hyperalgesia.