Ceftazidime pentahydrate (CP) and cefotaxime sodium (CS) are semisynthetic cephalosporin antibiotics and are used to treat a variety of diseases worldwide. In order to explore the efficiency of a medicinal compound, it is important to have a deep understanding of its solution and physiochemical behaviour along with its interaction with biological molecules. In this regard, the solution of two drugs i.e., ceftazidime pentahydrate (CP) and cefotaxime sodium (CS) were investigated in detail. The physicochemical properties of drugs solutions and their interaction with deoxyribonucleic acid (DNA) were studied in water under varying experimental parameters. In the present study the physicochemical properties such as density, viscosity, surface tension, and conductance of aqueous solution, having various molar concentrations, of CP and CS were traced out at different temperatures. Five various concentrations (0.05, 0.1, 0.15, 0.2, and 0.3 mol dm−3) of each drug in an aqueous medium were prepared separately, and the physicochemical properties of each solution, were studied individually at temperatures such as 293, 303, 313, 323, and 333 K respectively. Most of these parameters have shown different behaviour with varying concentration of solution and temperature of the medium. In addition, these drugs showed a spontaneous surface-active and association behaviour in aqueous solutions and drug DNA solution. The flow behaviour, surface properties, volumetric behaviour and solute–solvent interaction of this drug were prominently influenced by experimental variables. UV-Visible spectroscopy was also used to study the interaction of these drugs with DNA in aqueous media in detail. Calculated values of binding constants (K
b) for all drug–DNA are positive, indicating constructive binding and interactions between the molecules. In addition the binding efficiency of ceftazidime pentahydrate was found more than that of cefotaxime sodium. The interaction of drug–DNA was not only affected by the nature of the drug but also by the drug-to-DNA ratio and nature of the medium used.