The Gastroenterology Professionals at The Gastroenterology Clinic & Endoscopy Center, Inc. are pleased to welcome you to our practice. We want all our patients to be informed decision makers and fully understand any health issues you face. ... PATIENT PORTAL. ... Ohio 44266 Phone: 234-703-4334 Fax: 330-235-9261. Warren Office 1622 E. Market St..