Objective: To evaluate the synergistic effect of antimicrobial plant extracts from traditional medicinal plants on standard microorganism strains. Method: In the present study, eight plants (extracted with five different solvents) were screened for antibacterial activity against four gram negative and four gram positive strains by micro-broth dilution assay. Afterward, antimicrobial chloroform plant extracts were evaluated for synergistic effect with antibiotics against all the selected bacteria. Results: Chloroform extract of A. pungens, D muricata, S quitoense and G celosides exhibits antibacterial potential against all the bacterial strains. Almost all extracts shows synergistic effect with gram-positive bacteria while in case of gram-negative C coloynthis fruit and D muricata extracts shows synergistic interaction with antibiotics. Conclusion: The mixture of plant extract with antibiotics shows lower MIC. The plant extract do not exhibiting significant MIC were also found to show synergistic effect with antibiotics. It means plant extracts improves the activity of antibiotics. It can be inferred that the mixture of antibiotics and herbal remedies of these plant can be further evaluated to treat those infectious diseases that are caused by tested bacterial strains.