Abstract Severe anemia contributes significantly to child mortality in sub-Saharan Africa. Blood transfusion is used in emergencies but carries risks. In BMC Medicine, Olupot-Olupot and colleagues report the findings of a phase II trial in children with severe anemia in Eastern Uganda. They provide important early safety and efficacy data supporting large volume whole blood transfusion (30 ml/kg) compared with the World Health Organization recommendation of 20 ml/kg. Large volume transfusions result in more rapid and frequent correction of severe anemia; they can be expected to reduce the risk of transfusions, and help manage the scarce resource of donor blood. However, severe anemia arises from varying combinations of acute, sub-acute and chronic etiologies. The Fluid Expansion As Supportive Therapy study reminds us that the risks and benefits of even simple interventions are complex, and that rapid normalization of physiology may not always be the best strategy. There is no substitute for high quality evidence and to this end we strongly support Olupot-Oluput and colleagues’ call for a definitive trial of large volume transfusions in severe anemia. Please see related research article http://www.biomedcentral.com/1741-7015/12/67/abstract .