Hosny NS, El Khodary SA, El Boghdadi RM, et al. - Researchers conducted this parallel, prospective, double-blinded, randomized controlled trial to evaluate the impact of Neem vs 2.5% NaOCl as root canal irrigants on the intensity of postoperative pain and amount of endotoxins following root canal treatment of mandibular molars with necrotic pulps. This investigation was carried out at the out-patient clinic of the Endodontic Department, Faculty of Dentistry, Cairo University, Egypt. Using computer software, 50 healthy patients with mandibular molars with necrotic pulps were randomly assigned into two equal groups. Root canals were irrigated with Neem in the intervention group, while 2.5% NaOCl was used in the control group. During all follow-up times, there was no substantial difference between Neem and 2.5% NaOCl in terms of decreasing the severity of postoperative pain, except at 24 hours after instrumentation, where Neem was correlated with lower pain intensity. Both irrigant significantly reduced endotoxin levels but did not completely remove endotoxins from root canals of mandibular molars with necrotic pulps.