 The incidence of cognitive decline related to CPB ranges from 20 to 80, which may affect length of hospital stay, quality of life, the rehabilitation process, and work performance.However, there is no method to prevent the decline.Gastrodin,the active constituent of gastrodia elata, has been widely used for the treatment of paralysis, hemiplegia, headache, vertigo, and Alzheimers disease. Gastrodin is safe. No severe side-effect has been observed in the treatment. We postulate that gastrodin would attenuate the causative parameters of cognitive dysfunction related to CPB and would be an effective drug to prevent the decline as a result. 