Abstract

In 21 patients with megaloblastic anaemia associated with the tropical malabsorption syndrome serum vitamin B₁₂ levels have been measured serially before and during parenteral folic acid therapy.

In 11 patients there was a significant rise in serum B₁₂ levels, reaching a peak three to 17 days after starting the folic acid. In three of these cases, absorption of labelled B₁₂ was the same before and after the administration of folic acid. In two cases there was a fall in serum B₁₂ levels and in seven there was no change. In one case small amounts of folic acid produced no change in serum B₁₂ levels, whereas larger doses produced a prompt but transient rise.