These differences are highly significant (p < 0·0001). The ratio of AFB1 to AFM1 was higher in the sera and urines of kwashiorkors than in controls, suggesting that the normal transformation of AFB1 to AFM1; may be impaired in kwashiorkor with consequent increase in transformation of AFB1 to aflatoxicol. The study therefore provides evidence of differences in the metabolism of aflatoxins in children with kwashiorkor compared with children with other forms of malnutrition and normally nourished children and confirms the association between aflatoxins and kwashiorkor contained in a preliminary report on this work.