Iron and B12
with crohn's disease
can have more than 1 cause as both iron
deficiency and B12 deficiency are common as is anemia of chronic disease.
First and foremost, you need to get your crohn's disease under control. Second, a daily iron suppliment (325 mg of ferrous something) and a daily B12 suppliment (1000mcg) generally will do the trick. Occasionally B12 injections are needed.