The fundamental idea of chemistry is that the physical and chemical properties of molecules are determined in terms of their topological and electronic structures. It is widely accepted that the structural formula of an organic compound contains all its chemical,biological and physical properties coded in it.The drug- bacteria interaction is nothing but simply a chemical process. Many drug active molecules act by binding specifically and all of the sites of a molecule are not active. Drug- bacteria interaction takes place not globally but locally.The QSAR and QSPR are the attempts to correlate structural or property descriptors of compounds with some of their specific biological activity in terms of some mathematical formulations.In this works, within the paradigm of QSAR/QSPR and using global and local reactivity descriptors of DFT and MO theory we have found a nice correlation between theoretically computed and experimentally determined drug activities.