Methylephedrine is generally harmless and is contained in many cough and cold preparations. Likewise, Chinese herbal drugs are considered to be effective and to have few side effects. A 32-year-old woman experienced ischemic stroke attributed to concomitant administration of a cough and cold preparation containing methylephedrine and a supplement containing Chinese herbal drugs. Computed tomography and magnetic resonance imaging of the brain showed acute infarctions bilaterally in the cerebellum. Conventional angiography and magnetic resonance angiography showed transient stenosis of the left vertebral artery. These findings suggested vasospasm or dissection, presumably related to hypertension and/or angiitis or vasoconstriction of large cerebral arteries leading to local thrombosis as a result of stasis and sympathomimetic-induced platelet activation. Combining methylephedrine and Chinese herbal drugs might carry a risk of stroke.