Full text can be accessed at http://www.sciencedirect.com/science/article/pii/S0378874101003701Two replicate experiments were carried out to verify the efficacy of Aloe species (Aloaceae) as used for the control of Newcastle disease (ND) in rural poultry in free-range systems among several communities in Tanzania. Four months old local chickens free of Newcastle disease antibodies were used. Following inoculation with ND virus, body weights, clinical signs, antibody levels and mortality were monitored. Results showed that there was reduced mortality rate and the severity of clinical signs during the acute phase of the infection in Aloe treated chickens compared with the non-treated ones. However, there was no significant effect of the Aloe on the antibody levels that were attributed to the recovery of the surviving chickens. The findings of this study suggest that Aloe secundiflora could be a potential candidate on the management of Newcastle disease in chickens. Further studies are in progress to identify the active ingredients of A. secundiflora against Newcastle disease virus.