The objective of our work is to examine the influence of prolonged administration of an opioid, on the course of the reparative process of a multiple post-injection wound inflicted upon a white rat’s skin, doing so by way of using light microscopy. The studies were carried out on 24 mature white male rats, aged 4.5-7.5 months, with weights of 130-150 g. For histological examination, the skin sections were stained with hematoxylin and eosin. The preparations were studied and photographed at the magnification of ob.х8, ey.x15 and ob.x40, ey.x10. The «Aver Media» computer system was employed for micropreparations photography. The set levels of light microscopy reveal that the administration of an opioid for a 2 week period does not affect the reparative process of a multiple post-injection wound. Moreover, in most wound canals, the formation of a complete regenerate can be seen. However, after 4 weeks of nalbufin administration, the processes of wound healing slowed and were complicated by the formation of microabscesses. After 6 weeks of opioid administration, destructive changes in the skin were detected. These, in turn, led to the incomplete regenerate formation in the multiple postinjection wound. The experimental results, hence, show the negative effect of prolonged administration of opioid on the reparative processes in the skin.