Thanks for putting your query up at HealthCareMagic. Hydroxyurea acts as a disease modifying agent in sicle cell disease. The exact mechanism is unknown. But hydroxyurea lowers the concentration of Hb S within a cell resulting in less polymerization of the abnormal hemoglobin. The mechanisms by which it increases Hb F are unclear. There are a number of theories. Probably it acts directly on late precursors to reprogram them to produce Hb F. A recent study has provided evidence for a nitric oxide-derived mechanism for Hb F induction by hydroxyurea. About dietary supplements: Foods. Good nutrition, while essential for anyone, is critical for patients with sickle cell disease. Some dietary recommendations include: Fluids are number one in importance. The patient should drink as much water as possible each day to prevent dehydration. Diet should provide adequate calories, protein, fats, and vitamins and minerals. Patients and families should discuss vitamin and mineral supplements with their doctors and nurses. Some studies claim that omega-three fatty acids, found in fish and soybean oil as well as dietary supplements, might make red blood cell membranes less fragile and possibly less likely to sickle, although no studies have proven this definitively. Vitamins. Patients should take daily folic acid and vitamin B12 and B6 supplements. Vitamin B6 may have specific anti-sickling properties. Some doctors recommend 1 mg folic acid, 6 microgram vitamin B12, and 6 mg vitamin B6. Foods containing one or all of these vitamins include meats, oily fish, poultry, whole grains, dried fortified cereals, soybeans, avocados, baked potatoes with skins, watermelon, plantains, bananas, peanuts, and brewer s yeast. Of note, folic acid can mask pernicious anemia, which is caused by deficiency of vitamin B12 and is more common in African-Americans than other populations. I hope that helps. Feel free to revert back with further queries if any.