Abstract IT HAS generally been assumed that diseases of the intestinal tract interfere with nutrient absorption. Quantitative data have been lacking on the amount of absorptive impairment or the periods during the disease cycle when it occurred. Stafseth (1931) observed that rickets appeared more frequently or was more severe in birds suffering from coccidiosis. Erasmus et al. (1960) demonstrated decreased liver storage of vitamin A in chicks suffering from coccidiosis caused by a combination of E. tenella and E. acervulina. The decrease was particularly marked 1 week after the administration of the oocysts. These two reports suggest the occurrence of either absorptive impairment or excessive nutrient excretion in birds having coccidiosis. However, several groups (Edgar, 1958; McLoughlin et al., 1960; and Panda and Combs, 1964) have noted periods of increased rate of weight gain during recovery from coccidiosis. Panda and Combs (1964) suggested that this growth rate increase was due to …