1. Indol, orally administered, causes anemia when certain deficient diets are fed.
2. The same amount of indol causes no considerable hematologic disturbance when normal diets are fed.
3. The anemia can be cured by supplementing the diet with liver extract, or by substituting a normal diet for the deficient diet.
4. Neither the diet alone nor the administration of indol alone produces marked anemia under the experimental conditions observed.