Traditionally, Cham dang-gui (Angelica gigas Nakai) is one of the most popular herbal medicines in Asian countries including Korea. A. gigas has been used as a functional food product for treatment anemia, women's health care, a sedative, an anodyne or a tonic agent. Decursin and decursinol angelate isolated from the roots of A. gigas are pyranocoumarin compounds. Recently, as the global herbal medication market is increasing, investigations about pharmacological effects of decursin and decursinol angelate are rapidly increasing. We summarized previous studies about pharmacological effects of decursin and decursinol angelate, and reviewed relation with pharmacological effects of decursin and decursinol angelate on human disorder, focused on the approach for new drug development. Pharmacological effects of decursin and decursinol angelate were classified as anti-tumor activity, anti-bacterial activity, improvements of the circulating system, inhibition of cytochrome P-450 activity, anti-inflammation activity, anti-oxidant activity and cognitive-enhancing activites. The activity of A. gigas with improvement of the circulating system may have wide therapeutic potential for circulatory diseases, including diabetes, hyperlipidemia and atherosclerosis. Also, anti-inflammation activity A. gigas may be beneficial for the treatment and prevention of asthma, atopic dermatitis and rheumatism arthritis. This relation could potentially lead to the development of herbal new drugs. In order to development a new drug containing decursin and decursinol angelate, it is also necessary to consider the safety profile, and the information in this review would contribute to development a new drug from herbal medicine.