Trend analysis did not reveal a positive dose related trend in mortality rate Intergroup comparison, using the Chi-square test, showed a significantly(p 0.05 - 0.01)lower mortality from lunar month 20 to the end of the study at 500 mg/kg.Mortality rates at 2000 mg/kg and at 5000 mg/kg were comparable with that of the control group.Trend analysis did not reveal a positive dose related trend in mortality rate.The Chi-square test revealed no differences in mortality rate between groups.The overall mortality rate was as follows:Test for positive dose-related trend(a)Luner month(a)Peto monograph, WHO, IARC, Lyon, 1980, pp. 386 - 387, dose levels 0, 1, 2, 3.(b)Number observed/number at risk(c)Number of animals(dead or preteminally sacrificed)/total number of animalsCumulative per lunar monthX:Number of animals dead or sacrificed at stated periodMost individually recorded clinical observations were features normally encountered in ageing rats.They occurred in dosed and control groups and the incidence of the observations was comparable between groups.In mis respect the most frequently encountered clinical observations were bad condition and subcutaneous masses in both males and females.The following differences between the control group and the dosed groups were noticed:soft feces:this observation was made during the first year of the study in a few males and females dosed at 5000 mg/kg.