The worldwide use of natural products including medicinal plants has become more important in primary health care for various pharmacological effects including antimicrobial activity. Further, it is being appreciated that with increased incidence of resistance to antibiotics, natural products especially from medicinal plants could be interesting alternatives. In this regard a study was conducted to investigate antibacterial activity of a Unani formulation containing (i) Sonth (Zanjbeel) (Zingiber officinale) (ii) Suranjan (Colchicum luteum) and (iii) Elwa (Aloe vera). The alcoholic and hydro-alcoholic extracts dissolved in DMSO (Dimethyl Sulphoxaside) were used to determine antibacterial activity by Agar Well Method. Zone of Inhibition (in mm) was taken as the parameter of measurement against a number of bacterial strains viz. Staphylococcus aureus, Streptococcus mutans, Bacillus cereus, Corynebacterium xerosis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Klebseilla pneuomoniae. The effi cacy of Unani formulation against Bacillus cereus and Pseudomonas aeruginosa, was found even better than Ciprofl oxacin and Amikacin, respectively. The study demonstrated that Unani formulation possesses signifi cant antibacterial activity and can be used in infectious diseases caused by a number of Gram +ve and Gram -ve microorganisms.