To assess the effect of oral L-glutamine on: (a) frequency of hospitalizations for sickle cell pain; (b) frequency of emergency room/medical facility visits for sickle cell pain; and (c) hematological parameters (hemoglobin, hematocrit, and reticulocyte count); and to assess the safety of L-glutamine as a therapy for sickle cell anemia as evaluated by adverse events, laboratory parameters, and vital signs.