Knowledge of different kinds of intermolecular interactions present in drug-bile salts system was procured from volumetric, compressibility, and viscometric studies. The measured density (rho), speed of sound (u), and viscosity (eta) of sodium salt of cholic acid and deoxycholic acid, namely sodium cholate (NaC) and sodium deoxycholate (NaDC) respectively, in aqueous solutions of metformin hydrochloride (an antidiabetic drug) were meticulously used to calculate various parameters that are known to give valuable information on the presence of different types of interactions in a mixture. The alteration in the strength of such interactions by temperature and concentration was also analyzed by varying temperature from 293.15 to 313.15 K at a regular interval of K and drug concentrations of 0.005, 0.010, and 0.050 mol.kg(-1). The variations in enumerated parameters were interpreted by applying well-known cosphere overlap model that confirms the presence of a significant amount of hydrophobic/electrostatic interactions between drug and bile salts. From this, the dominance of electrostatic and hydrophobic interactions at low and high bile salt content, respectively, was observed in the system. Moreover, the knowledge on interactions was strengthened by H-1 NMR spectroscopic studies. The interactional knowledge may be considered to be helpful to increase the use of bile salts (as penetration enhancer) in the pharmaceutical world.