Blood glucose, liver cyclic AMP (cAMP) levels, and platelet count were studied at different times during a 12 h interval after intravenous (i.v.) endotoxin injection (40 mg/kg) in mice. 2. Blood glucose and liver cAMP levels showed a progressive decrease in endotoxic mice and the decrease was significant after 8 and 12 h. 3. Dipyridamole (50 mg/kg) administered intraperitoneally (i.p.) 7 h post-endotoxin improved blood glucose and liver cAMP levels. 4. Platelet counts were decreased after 1 h in endotoxic mice and remained decreased up to 8 h. Dipyridamole administered soon after endotoxin improved platelet counts in endotoxic mice and increased survival rate to 100%.