The polyphenol natural product curcumin has been the subject of numerous studies over the past decades, which have identified and characterized the compound's pharmacokinetic, pharmacodynamic, and clinical pharmacological properties. In in vitro and in vivo model systems, curcumin displays potent pharmacological effects, by targeting many critical cellular factors, through a diverse array of mechanisms of action. Despite this tremendous molecular versatility, however, the clinical application of curcumin remains limited due to poor pharmacokinetic characteristics in human beings. The current trend is to develop and utilize unique delivery systems, chemical derivatives, and chemical analogs to circumvent these pharmacological obstacles, in order to optimize the conditions for curcumin as a chemopreventive and chemotherapeutic agent in diseases such as cancer, diabetes, obesity, Alzheimer's disease, and inflammatory disorders. The present work seeks to review recent studies in the basic pharmacological principles and potential clinical applications of curcumin.