GSK143 dihydrochloride is an orally active and highly selective spleen tyrosine kinase (SYK) inhibitor with a pIC50 of 7.5. GSK143 dihydrochloride inhibits phosphorylated Erk (pErk: pIC50=7.1). GSK143 dihydrochloride reduces inflammation and prevents recruitment of immune cells in the intestinal muscularis in mice.