A new granulocyte collection method employing discontinuous flow centrifugation and low donor dose of hydroxyethyl starch (HES) is presented. Following the procedure, the increase in serum polysaccharide concentration was 100 mg/dl, about 20% of that seen after standard discontinuous flow leukapheresis. The average efficiency of granulocyte collection by this method is about 64%. The average yield of WBC from 2,600 ml of donors' whole blood is 1.64 +/- 0.54 x 10(10) (mean +/- 1 SD) and the average granulocyte yield is 1.33 +/- 0.51 x 10(10) (mean +/- 1 SD). The granulocytes were shown to migrate to the sites of infection in vivo. This approach is an improvement over standard discontinuous flow leukapheresis because of the high efficiency of granulocyte collection and because multiple procedures are possible without exposing donors to more HES than is currently given during a single procedure.