Chlorogenic acid, i.e. 1, 3, 4, 5-tetrahydroxycyclohexanecarboxylic acid-(3, 4-dihydroxycinnamic acid ester), exists in a plurality of plants, and also, high purity chlorogenic acid can be prepared through synthesis. Chlorogenic acid has a lot of biological activity, such as antibacterium, antivirus, antioxidation, antitumor and the like. However, there exists no report and research on oral preparations prepared by high purity chlorogenic acid and application of the preparations in clinics. In the invention, high purity chlorogenic acid is extracted from plants or obtained through synthesis, and is then added with a proper amount of accessories, thus obtaining oral preparations like tablets, capsules, granules, oral solutions, etc. The preparations provided in the invention can be applied in clinics for treating cardio-cerebrovascular diseases, infections, hepatitis B, tumors and other diseases, and also can be used in health care medicines for heat clearing and detoxifying, face nursing and skin moistening, as well as hangover relieving, etc.