ABSTRACT
Based on the correlation between Qi and blood in traditional Chinese medicine， the collateral disease theory puts forward that the Qi-collateral go hand in hand with the vessel-collateral of the brain， and to be as close as lips to teeth in structure and function， which is an important basis for the function of brain governing mind. And this theory proposes that deficiency/stagnancy of collateral-Qi， stagnation of collaterals and loss of consciousness are the main pathogenesis of Alzheimer's disease（AD）， which is different from the research strategy of modern medicine focusing on neurons. It is suggested that it is necessary to treat AD from two aspects， including neuronal protection（elimination of pathological products such as β-amyloid and phosphorylated tau protein） and cerebral microvascular protection（protection of cerebral microvascular structure and function， promotion of therapeutic angiogenesis and increase of cerebral blood flow. Tongxinluo capsules is a representative drug for dredging collaterals developed under the guidance of the therapeutic principle of collaterals need circulation， it can protect microvessels and play a neuroprotective role mediated by vascular protection. Clinical studies have confirmed that Tongxinluo capsules can effectively treat AD， vascular dementia and cognitive impairment related diseases， which can provide new ideas and effective treatment ways to prevent and treat AD from neurovascular protection in a comprehensive manner.