Although Bell's palsy is the most common acute facial paralysis, the cause of it is still unknown. This made the treatment for it remain very limited. Many methods are simply symptomatic treatment. Up to now we have known that Bell's palsy is related to viral infection and the pathomechanism of Bell's palsy involves inflammatory oedema and entrapment neuropathy in the narrow bony facial canal. So treatment plans for Bell's palsy mainly focus on antiviral therapy, relieving inflammatory oedema and accelerating facial nerve recovery. Sodium beta-aescin is derived from horse chestnut and its major constituent is aescigenin which has been approved by China national drug standard. The pharmacologic action of sodium beta-aescin is to relieve tissue oedema, recover vasopermeability and eliminate pressure caused by oedema. Nowadays sodium beta-aescin has been widely used clinically for encephaledema or tumefaction caused by trauma or operation. It also can be used for treating disease of digestive system and increasing intravenous tension and improving microcirculation. Although many papers had been published on the anti-edema effects of sodium beta-aescin, little was known about the effects in treating oedema complicated by Bell's palsy.