1. Two experiments were carried out to determine whether administration of lactate to biotin‐deficient chicks induced fatty liver and kidney‐syndrome (FLKS).
2. The results suggest that increased serum lactate concentrations are a consequence of the syndrome rather than a contributory factor in its incidence.
3. The increase in liver lipids of birds affected by FLKS was not associated with an increase in the specific activity of the hepatic lipogenic enzyme acetyl CoA carboxylase except when birds developed FLKS spontaneously in experiment 2.
4. Some biotin‐deficient chicks did not show physical symptoms of deficiency although mean liver biotin concentrations were low (0.31μg/g liver).