Background. Ischaemic stroke is one of the leading causes of death and disability worldwide. Selective intracarotid cerebral hypothermia is one of the promising methods to prevent ischaemic stroke. However, currently available studies do not allow us to conclude the effectiveness of applying this method in humans and assess its effect on the system temperature.Aim. To investigate the effect of selective intracarotid cerebral hypothermia on the size of ischaemic stroke in large pigs, determining the optimal period of hypothermia and the severity of the effects of intracarotid hypothermia on the system temperature.Methods. The study was conducted on mini-pigs weighing 30–70 kg and included two stages. During the first stage, pigs were divided into two groups: control (n = 4) and intracarotid hypothermia for 3 h, exciting periods before and after reperfusion (n = 2). During the second stage, animals were also divided into two groups: hypothermia group within 1.5 h before reperfusion (n = 2) and hypothermia group within 1.5 h after reperfusion (n = 2). The technique for modelling ischaemic stroke was the same as in all groups and consisted of frontotemporal craniotomy and compression of the middle cerebral artery for 3 h. Intracarotid hypothermia was performed by infusing + 4 °C NaCl solution in the ascending pharyngeal artery. At 48 h after starting the experiment, a brain magnetic resonance imaging scan was performed to determine the size of the stroke.Results. The mean size of the stroke focusing in the control group was 10.75%, in the hypothermia group before reperfusion (10.95%) and in the hypothermia group after reperfusion (1.65%) of the volume of the cerebral hemisphere. The stroke size in the hypothermia group for 3 h could not be determined due to complications that developed in animals intraoperatively and postoperatively. The effect of intracarotid hypothermia on the systemic temperature in an animal weighing 65 kg was 0.4 °C.Conclusion. Based on the study results, a marked decrease in the focus of ischaemic stroke was found with the use of intracarotid hypothermia within 1.5 h after reperfusion. Intracarotid hypothermia was found to do not have a pronounced effect on the system temperature. Received 2 May 2020. Revised 20 May 2020. Accepted 25 May 2020. Funding: The work is supported by a grant of the Russian Foundation for Basic Research (project No. 18-415-540025). Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and study design: E.I. Fartakov, V.V. Lomivorotov, E.I. Kretov, A.R. TarkovaData collection and analysis: D.U. Malaev, A.A. Boykov, A.A. Prokhorikhin, D.V. Volchenko, I.S. Zykov, P.O. SeleznevDrafting the article: E.I. Fartakov, D.U. Malaev, A.R. TarkovaCritical revision of the article: E.I. Kretov, V.V. Lomivorotov, V.I. Baystrukov, N.I. Grachev, D.S. Sergeevichev, A.M. ChernyavskiyFinal approval of the version to be published: E.I. Fartakov, V.V. Lomivorotov, D.U. Malaev, A.R. Tarkova, A.A. Boykov, A.A. Prokhorikhin, D.V. Volchenko, I.S. Zykov, P.O. Seleznev, V.I. Baystrukov, N.I. Grachev, D.S. Sergeevichev, A.M. Chernyavskiy, E.I. Kretov