[Gateway Gastroenterology | Gastroenterology & Hepatology located in Chesterfield, Saint Louis, Ballwin and Des Peres, MO Trusted Gastroenterology & Hepatology serving the patients of Chesterfield, Saint Louis, Ballwin and Des Peres, MO. Contact us at 314-529-4900 or visit us at 121 Saint Luke's Center Drive, Suite 406, Building A, Chesterfield, MO 63017.]