The flavonoids and essential oils contained in five medicinal plants Rheum palmatum (Rp), Cassia angustifolia (Ca), Glycyrrhiza glabra (Gg), Cichorium intybus (Ci) and Matricaria chamomilla (Mc) from different families were extracted, screened against different antibiotic resistant bacterial strains (ARB) (six obtained from pharmaceutical products and twelve from hospital drains) and identified based on GC/MS chromatographic technique. The results showed that only Rp, Ca, and Gg extracts exhibited antibacterial activity against two bacterial strains out of six (33.33%) and three out of twelve (25%). The combinations were done between the three extracts and synergism action was obtained. Different concentrations exhibited slight inhibitory effect at 10% as compared with great inhibitory effect at 30%. The flavonoids and volatile oils contents were (2.88/0.2%); (1.6/0.1%); (2.68/0.25%) for Rp, Gg and Ca extracts, respectively.