STAT3-SH2 domain inhibitor 1 is a potent Src Homology 2 (SH2) Domain of STAT3 (STAT3-SH2 domain) inhibitor with a K d value of 1.57 μM. STAT3-SH2 domain inhibitor 1 inhibits STAT3 signaling transduction and transcriptional activation. STAT3-SH2 domain inhibitor 1 induces apoptosis in gastric cancer cells. STAT3-SH2 domain inhibitor 1 can be used in research of cancer.