Aqueous extraction from fresh leaves of Acacia nilotica by Ultrasound Assisted Extraction (UAE)method was proposed in the present study. The intended method was occupying most of the features of the green extraction method. Efficiency and efficacy of the proposed extraction method was compared with the conventional extraction method and found satisfactory performance. The % yield (extraction efficiency) of the proposed method was observed higher than the conventional methanol and ethanol extraction. Similarly presences of tested phytochemicals werealso higher than the conventional method.Antimicrobial study (extraction efficacy) was performed against S. aureus(Gram +ve) and S. dysenteriae (Gram -ve) bacteria and found almost similar antimicrobial activities with the conventional crude extract. Based on the experiment the Aqueous UAE method may be standardized as an effective green extraction procedure

Keywords : Green Extraction, Ultrasound Assisted Extraction, Staphylococcus Aureus, Shigella Dysenteriae.