Background: Vasospasm occurs commonly in the intracranial arteries as a complication of subarachnoid haemorrhage. On the other hand, extracranial Internal carotid artery (ICA) vasospasm is scarce, and it may occur due to mechanical manipulation during cerebral angiography. We report a case of cervical carotid artery vasospasm during diagnostic cerebral angiography, which caused anterior cerebral artery territory hypoperfusion, to discuss potential risk factors. Case description: For a 22-year-old female with a ten-year history of epilepsy on multiple drugs, brain magnetic resonance imaging (MRI) showed frontal periventricular developmental venous anomaly. Diagnostic catheter cerebral angiography was used to better identify the vascular abnormality. In the procedure, extra steps were performed, including instruments being sterilized with CIDEX® OPA Solution (phthalaldehyde as the active ingredient), the reuse of the set including the catheters more than twice or triple times, and cold temperature of normal saline that was used in the flushing procedure. Under conscious sedation, the procedure went uneventful until the catheterization of the left carotid artery was performed, where severe vasospasm was noticed in the extracranial ICA, followed by cessation of flow in the ipsilateral ACA. Pulling the catheter to a more proximal location in the extracranial ICA was performed to alleviate the vasospasm. It took twelve minutes for the circulation to be restored, and that was under continuous irrigation and flushing. The patient did not develop any symptoms throughout the procedure or post-procedural course. Conclusion: Chemical irritation from the sterilizing agent and reuse of the catheters could cause extracranial ICA vasospasm.