The antitumor efficiency of gold nanorod plasmonic photothermal therapy (PPTT) was evaluated experimentally. The rat cholangiocarcinoma line PC-1 was used as a tumor model. Exposure of tumors to 808-nm laser radiation was performed, and the noninvasive temperature monitoring of the tumor tissue was carried out using infrared imager. The growth rate kinetics and morphological alterations of transplanted liver tumors, as well as indicators of lipid peroxidation activity and autointoxication in rat serum, were studied. The activation of lipid peroxidation and the development of autointoxication were detected after PPTT. The results not only demonstrate the antitumor efficacy of the proposed therapeutic technology but also reveal the side effects in the presence of peroxidation products in systemic circulation.