Curcumin quite possibly represents one of the most diverse therapeutic agents yet isolated from natural sources. Therapeutic benefits of this extraordinary natural compound have been demonstrated during treatment of a variety of diseases, including cancer, inflammatory processes, immunological disorders, Diabetes, and oxidative stress often associated with hyperlipidemia. Due to its unique molecular chemical structure and functional groups, curcumin may bind with and subsequently either inhibit or activate a variety of endogenous biomolecules, including enzymes, receptors, signaling molecules, metals, transcription factors, and even certain proteins located in cell membranes. In fact, curcumin exerts pharmacologically useful effects through non-covalent interactions with biomolecules. With so many varied biological targets, curcumin (a polyphenol) elicits numerous pleiotropic effects, which is therapeutically advantageous owing to the fact that many pathological disease states involve more than one signaling pathway, receptor, protein/enzyme, or gene. In this paper, we will discuss the underlying mechanisms responsible for the chemical interaction of curcumin with selected classes of biomolecules, rather than attempt to provide an exhaustive list of each and every biomolecule with which curcumin may chemically interact.