An 87-year-old man developed orolingual angioedema followed by cardiovascular instability and progression of stroke during treatment with alteplase and enalapril.The man, who had a history of hypertension and chronic kidney disease, was hospitalised with motor aphasia, dysarthria, and right hemiparesis. He had been taking antihypertensive medications, including enalapril at 10mg daily [route not stated]. Upon hospitalisation, an MRI showed an ischaemic lesion in the left frontal lobe including the insular cortex and severe stenosis of the left middle cerebral artery. Therefore, he received IV infusion of alteplase [dosage not stated] treatment 140 minutes after the onset of symptoms. His condition improved but by the end of alteplase infusion, he experienced swelling on the right side of his tongue with a haemorrhage on its surface. Later, his HR suddenly started to decrease at 2 hours from the end of the alteplase treatment, followed by the dropped in his BP. Within 15 minutes, his HR and BP came back to normal level, respectively. However, his symptoms deteriorated and he developed total aphasia and complete right hemiplegia. The National Institutes of Health Stroke Scale score increased to 23. Brain MRI revealed expansion of the ischemic lesion to include the entire territory of the left MCA and left MCA occlusion was identified using MRA. His magnetic resonance angiography revealed the asymmetrically swollen tongue with no parenchymal haematoma, confirming right sided orolingual angioedema.The man was immediately treated with hydrocortisone. Within 2 days, the oedema disappeared. Author comment: "careful attention to possible development of orolingual angioedema remains critical because it may accompany cardiovascular instability and affect the severity of stroke, as observed in the following case." "Several clinical observations have previously indicated that the risk of [alteplase]-associated orolingual angioedema also increases with the concomitant use of ACE inhibitors" Kageyama T, et al. Cardiovascular instability preceded by orolingual angioedema after alteplase treatment. Internal Medicine 55: 409-412, No. 4, 15 Feb 2016. Available from: URL: http://doi.