Butylphthalide, also known as 3-n-butylphthalide or NBP, is an antioxidant and one of the chemical constituents in celery oil, along with sedanolide, which is primarily responsible for the aroma and taste of celery. Butylphthalide may be useful for the treatment of hypertension and may have neuroprotective effects. In 2004, NBP was approved in China for the treatment of cerebral ischemia. Minor side effects were observed in preclinical and clinical studies. The minor bioactivation pathway of NBP was proved to be medicated via sulfation of 3-OH-NBP.