LY294002 is a potent and specific cell-permeable inhibitor of phosphatidylinositol 3-kinase (PI3-kinase). LY294002 at a concentration of 50uM completely abolishes the PI3-K activity of intact neutrophils stimulated with fMet-Leu-Phe, without apparent cell toxicity. While concentration of 50uM is observed to be efficacious for inhibiting PI3-K activity in stimulated neutrophils, this concentration produces no significant inhibition of other kinases including PKC, PKA, MAP kinase, S6 kinase, EGF receptor tyrosine kinase, Src, PI4-kinase, diacylglycerol kinase, or rabbit kidney ATPase. This compound is a useful tool for identifying cellular event that are regulated by the PI3-kinase/Akt axis, and is observed to induce apoptosis in many cell types by blocking the PI3-kinase/Akt anti-apoptotic pathway.