Background: Acute ischemic stroke (AIS) is a leading cause of morbidity and mortality worldwide. Human urinary kallidinogenase (HUK), a glycoprotein extracted from male urine currently used in China for enhancing cerebral perfusion5, plays a neuroprotective role including promoting angiogenesis, enhancing cerebral perfusion and suppressing the inflammatory response in animals and in patients with respect to regulating the kallikrein-kinin system. In previous clinical research, neurological function scores and cerebral perfusion scans were largely used to evaluate the efficiency of HUK. However, the mechanisms of Further well-conducted, randomized controlled studies using HUK are currently lacking. Objective: To assess the Human urinary kallidinogenase effects on brain metabolite and cerebral perfusion changes using magnetic resonance spectroscopy and CT perfusion in patients with AIS. Methods: The investigators plan to do a single-centre randomized, double-blind, controlled trial in which ischemic stroke patients will be randomized to treatment with either HUK or regular treatment within 72 hours of symptom onset. The study includes two MRS and two CTP scannings (before and after 2 week treatment) for all randomized subjects. The endpoints will include improvement of the NIH Stroke Scale (NIHSS) score from baseline, modified Rankin scale (mRS) score and Barthel index at 14 days. EvHUKMRS will test the following hypotheses: HUK enhanced N-acetylaspartate (NAA) and cerebral blood flow (CBF) 14 days after treatment compared with control group. HUK group compared to control group when administered 72 hours after onset of AIS improves recovery and functional outcome as assessed by improvement of NIHSS score , mRS score and BI score on day 14 post-stroke. A positive result will have a significant impact in the management of AIS and pave the way for future studies aimed at finding the optimal dose and formulation of HUK for treating acute ischemic stroke.