Microorganisms have developed resistance due to indiscriminate use of many antibiotics which are also associated with severe adverse effects. To overcome these problems plants and their products provides a better substitute for treating infectious diseases. Afsanteen (Artemisia absenthium), flowers of Banafshah (Viola odorata) and Bisheri booti (Aerva lanata) are used in Unani System of Medicine since long time either as single drug or in compound formulation. All the three drugs were screened for antibacterial activity against different strains of gram positive and gram negative bacteria such as Bacillus sp. Staphylococcus aureus, Streptococcus pyogenes Escherichia coli, Citrobacter sp., Klebsiella sp. Salmonella typhimurium and Proteus sp. etc. The Aqueous and alcoholic extracts of these crude drugs were used to determine antibacterial activity by disc-agar diffusion technique at four concentration levels (100, 50, 25 and 12.5μg/disc) and compared with standard drug ciprofloxacin at concentration of 5 μg/disc. Zone of Inhibition was taken as the parameter for the assessment of antibacterial activity. Of all the drugs tested, the alcoholic extract of Viola odorata was found to be the most active against Salmonella typhimurium at the doses of 50 and 100μg/disc. Furthermore, before testing these drugs for antimicrobial activity, their samples were also checked for authenticity based on certain physico-chemical parameters.