p38 MAP Kinase Inhibitor IV is a cell permeable sulfone compound which functions as an ATP-competitive inhibitor of p38α and p38β MAP Kinases. In addition, p38 MAP Kinase Inhibitor IV inhibits p38&gamma/δ, ERK1/2, and JNK1/2/3 to a lesser extent. Furthermore, studies indicate that p38 MAP Kinase Inhibitor IV suppresses LPS-induced IL-1&beta release from hPBMC more effectively than SB 203850. Since MAP Kinases are responsible for signal transduction in cascade controlling cellular responses the inhibitor can possibly be used to inhibit apoptosis and other responses to stress stimuli.