Delayed type hypersensitivity (DTH) in male pups was inhibited when exposed to ethephon during pregnancy and lactation period. Hemolytic plaque number in spleen of male pups could be decreased by ethephon when exposed during pregnancy and lactation period. Ethephon showed developmental immunotoxicity on male offspring. The expression or phosphorylation of Bcl11b, p-p38 in pups inhibited by ethephon when exposed during pregnancy and lactation period.