Objective: To evaluate the antibacterial efficacy of five Indian medicinal plants such as Acalypha indica L. (A. indica), Aerva lanata (L.) Juss. ex Schult. (A. lanata), Clerodendrum inerme (L.) Gaertn., Pergularia daemia (Forsk.) Chiov. and Solanum surattense Burm. f. against opportunistic bacterial pathogens isolated from HIV infected patients for the potential phytoconstituents in plant extracts. Methods: The opportunistic bacterial pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa, Salmonella typhi and Serratia marcescens from Gram-negative group and Staphylococcus aureus from Gram-positive group were isolated from HIV infected patients. The antibacterial efficacy of ethanolic extracts of selected medicinal plants was carried out by disc diffusion method. The potential phytoconstituents of medicinal plant extracts were identified by gas chromatography and mass spectrometry (GC-MS) analysis. Results: Among the five medicinal plants tested, A. indica and A. lanata showed the significant antibacterial activity. A. indica showed potential activity against Staphylococcus aureus and E. coli. A. lanata significantly exhibited antibacterial activity against E. coli, Salmonella typhi and Pseudomonas aeruginosa. A total of 19 phytoconstituents were identified in the ethanolic extract of A. indica and A. lanata by GC-MS analysis respectively. Conclusions: The results of the present investigation revealed that A. indica and A. lanata, possessed significant antibacterial activity when compared with the other plant extracts tested. The presence of 3-O-methyl- d-glucose by GC-MS analysis in both A. indica and A. lanata extracts has not been reported elsewhere in the literature and the findings in this study could be the first one to report.