Background Heat-related illnesses include symptoms such as heat syncope/cramps, heat exhaustion, and life-threatening heat stroke. Usually, a heat stroke causes cerebellar ataxia, cognitive impairment, dysphagia, and aphasia. We report a very rare case of a patient who developed severe heat stroke complicated by multiple cerebral infarctions. Case presentation An 80-year-old Asian woman was found lying unconscious at her house, with no air conditioner and closed windows; the highest outside temperature was 36.1 degrees C. She was brought to our hospital unconscious with a high bladder temperature (42.5 degrees C) and disseminated intravascular coagulation (DIC score 4). She was diagnosed with severe heat stroke and managed with rapid cooling, intravenous fluids therapy, antibiotic therapy, and anti-coagulation therapy for DIC. Anti-coagulation therapy consisted of treatment with recombinant thrombomodulin for 4 days (days 1-4) and recombinant antithrombin for 1 day (day 1). A head computed tomography (CT) and magnetic resonance imaging (MRI) examination were performed on day 3, because she was still unconscious. Diffuse-weighted imaging showed high-signal intensities, indicating multiple lesions. An intracranial magnetic resonance angiography showed normal results. Imaging indicated new multiple cerebellar infarctions complicated with DIC. A tracheotomy was performed on day 9 because her conscious condition had not improved. She was transferred to another hospital for subacute care on day 23. Conclusions Early management of heat stroke using anti-DIC, anti-bacterial, and fluid resuscitation therapy can help prevent complications such as intracranial hemorrhaging.