A case is presented of a child who had a megaloblastic anemia which was not responsive to vitamin B12 nor to folic acid. The erythrocytes were hypochromic and microcytic, but there was no response to iron or to pyridoxine. Neither parent and no siblings had evidence of thallassemia. The autopsy did not reveal evidence of Di Guglielmo’s disease.

A striking feature was the excretion of large amounts of orotic acid in the urine.

Improvement followed administration of adrenal steroid hormones without reversal of the megaloblastic marrow nor striking reduction in orotic acid excretion.

A seemingly complete hematologic remission and a remarkable reduction in orotic acid excretion followed the administration of a crude mixture containing uridylic acid and cytidylic acid while steroid hormones were continued. Before further studies could be made the child died of severe varicella.