Experience in the treatment of bites by the Mozambique spitting cobra. Naja mossambica mossambica Peters, is described, and it is shown that the predominant effect of the venom is cytotoxic. The gross pathology of the bite is presented. A large percentage of the bites (94%) occurred inside human dwellings, and of these, 81% occurred while the victims were asleep. The efficacy of the SAIMR's polyvalent antivenom was tested, and the evidence suggests that its effectiveness is indirectly proportional to the time which has elapsed between the bite and the administration of the antivenom. A comparison of the data with those presented by Warrell et al. in respect of bites by Naja nigricollis in Nigeria, shows that the clinical effects of bites by N. mossambica and N. nigricollis are closely related.