Wasp sting complicated by ischemic stroke is extremely rare in clinical practice， with more than 20 public case reports worldwide， and compared with general cerebral infarction， there is limited information on the pathophysiological mechanism and treatment of wasp sting-related stroke. Case Summary This article reports a case of a male patient， aged 25 years， who developed epileptiform seizure as the initial manifestation after wasp sting. The patient was diagnosed with ischemic stroke after cranial CT and MRI examinations. DSA showed no visualization of the right common carotid artery and its distal vessels. A few red thrombi were aspirated by endovascular intervention， and reexamination showed that the blood vessels were recanalized. However， the patient then developed post-cerebral infarction hemorrhagic transformation and cerebral herniation. Although the patient was given decompressive craniectomy， removal of intracranial hematoma， and systematic rehabilitation treatment， he still had an unsatisfactory prognosis and needed others to take care of his activities of daily living. This is the first report of secondary ischemic brain injury and hemorrhagic transformation after wasp sting in China. Cerebral vascular injury after wasp stings is a continuously progressive process. Therefore， physicians at initial diagnosis should be highly alert to the effect of wasp venom in causing delayed vascular injury， and related blood parameters should be monitored dynamically， such as D-dimer， coagulation function， and high-sensitivity C-reactive protein. Early inhibition of inflammatory response by antihistamines or steroids helps to delay the progression of the disease. Inflammatory response and coagulation dysfunction may be the main mechanisms of ischemic brain injury after wasp sting. Such patients tend to have a higher hemorrhagic risk of interventional treatment compared with the patients with general ischemic stroke.