HBG2 and methemoglobinemia: We discuss a case of a two-year-old male who developed severe persistent methemoglobinemia treated with multiple doses of methylene blue (MB), multidose activated charcoal, and vitamin C. Methylene blue infusion (rather than bolus dosing) aided in controlling this patient's methemoglobin (MetHb) levels and symptoms and may reduce the total needed dose.