Mitogen activated protein kinase (MAPK) is a type of intracellular serine/threonine protein kinase, which exists in most cells. It is an important signaling pathway that allows eukaryotic cells to transduce extracellular signals into cells to cause cell response. It affects the biological behavior of cells (such as cell proliferation, differentiation, transformation, apoptosis) by affecting the transcription and regulation of genes. There are three major families of MAPKs: ERKs, JNKs, and p38-MAPKs. The p38 signaling pathway is an important branch of the MAPK pathway that plays an important role in various physiological and pathological processes such as inflammation, cell stress, apoptosis, cell cycle, and cell growth. Four known p38 isoforms include p38α, p38β, p38γ, and p38δ. Through years of research, the p38-MAPK pathway has been found to be activated by hypertonic stimulation, heat shock, radiation, and other stress reactions. Thus, the p38-MAPK pathway is involved in a variety of stimulus-induced signaling cascades and p38 also shows a regulatory effect in apoptosis.