Caffeic acid is an organic compound that is classified as a hydroxycinnamic acid. Caffeic acid is naturally found in many agricultural products, such as fruit, vegetables, wine, olive oil, and coffee, and therefore, significantly present in human diet. Caffeic acid has been reported to have a wide variety of biological activities, including antioxidants, antithrombosis, antihypertensive, antifibrosis, antiviral and anti-tumor properties. Caffeic acid can be effectively employed as a natural antioxidant in various food products such as oils. Caffeic acid exhibits potent anticancer effect in HT-1080 cell line and that it may be used as an anticancer agent. Caffeic acid showed neuroprotective action against oxidative and DNA damage produced in the kindling epilepsy model, although they did not produce antiepileptogenic effect in vivo. Caffeic acid was effective in patients with primary immune thrombocytopenia. Detected in clinical trial caffeic acid-related adverse events were: mild nausea and elevation of liver enzymes.