The overall. objective of this study was to determine the effect of gossypol on human lymphocytes. Blood samples were taken from healthy donors and lymphocytes were cultured with various concentrations of gossypol (25-150 muM). The percentage of apoptotic cells was determined by assessing DNA fragmentation by agarose gel electrophoresis; morphological features of apoptosis were assessed by light microscopy. The concentrations of gossypol required to induce apoptosis in human lymphocytes without causing necrosis through cytotoxic effects were between 25-50 muM. (C) 2003 Published by Elsevier Ltd.