Raising the Hb is the only way to slow down bone marrow activity, and even then, some minors whose Hb is normal have very high RBC counts, indicating that in spite of the normal Hb, they are still producing too many red blood cells. The more I learn about thal, the more I see that there are no pat answers that apply to every thal. There are many things in the discussion about raising Hb. Wheatgrass in any form, folate, vitamin B-12, B Complex, magnesium, L-carnitine and vitamin E are all in that discussion. Minors are often wary of iron, but an iron rich diet may also have a positive effect on Hb, with the need dependent on the iron status of each person, without resorting to iron supplements, which are not a good idea over the long term. The body more easily absorbs iron from food than from supplements, so it's another factor in favor of a dietary approach.