Energy minimization calculations and quantum mechanical calculations on compounds of biological and pharmacological interest continue to give insights into and explanation of their modes of behavior, resulting in clues to their pharmacophores. The inhibition of the enzyme aldose reductase by a wide variety of compounds continues under investigation by QSAR techniques, as well as by energy minimization computations, quantum mechanics and stereochemical considerations. A model for the interaction of a wide range of types of compounds with aldose reductase has been proposed, and their common features obtained. Energy minimization and quantum calculations have been carried out on the various conformations of colchicine and isocolchicine to correlate binding properties with the energies and structures of their conformations. Various compounds showing promise against the AIDS virus are being systematically investigated to obtain structural and electronic properties which may help elucidate the mechanism of their action, and thus lead to improved forms.