Parent Page: Academic Departments id: 22555 Active Page: Facultyid:23541


Internal Medicine

Ralph T. Guild III, MD

Professor of Medicine

COMD 7400
800 Stanton L Young Blvd
Oklahoma City, OK


405-270-0501 x5313 (VA Office)
405-270-1529 (Fax)

Dr. Guild is a board-certified gastroenterologist and a professor at the OU College of Medicine. Dr. Guild sees patients at the Oklahoma City Veterans Affairs Medical Center and at OU Physicians. He has a special interest in diagnosing and treating patients with Gastroesophageal Reflux Disease and Peptic Ulcer Disease. Guild completed a fellowship and residency at the University of Florida after earning his medical degree at the OU College of Medicine.​

Academic Section(s):

Digestive Diseases


University of Oklahoma College of Medicine, Oklahoma City, OK
MD (1974)

Board Certification(s):

American Board of Internal Medicine
Internal Medicine (1977, non-expiring)

American Board of Internal Medicine
Gastroenterology (1981, non-expiring)



University of Florida, Gainesville, FL
Internal Medicine (1977)


University of Florida, Gainesville, FL
Gastroenterology (1981)


American Society for Gastrointestinal Endoscopy, 1989

Arkansas/Oklahoma Endoscopic Society, 1989

American College of Gastroenterology, 1988

Midwest Gut Club, 1988-1999

Oklahoma Society of Parenteral and Enteral Nutrition, 1986-1996

Central Oklahoma Gut Club, 1986

Duval County (Florida) Medical Society (Inactive), 1985-1986

Jacksonville (Florida) Gut Club, 1984-1986

Florida Emergency Medical Services Directors Association, 1984-1986

Florida Gastroenterological Society, 1981-1986

American Gastroenterological Association, 1981

American Society of Parenteral and Enteral Nutrition, 1980-1995

Clinical/Research Interests:

  • Colon cancer
  • Reflux disease
  • Diarrhea
  • Constipation


Clinical Trials

“A National, Randomized, 12-Week, Double-Blind, Placebo-Controlled Study to Assess the Safety and Efficacy of Plecanatide (3.0 and 6.0 mg) in Patients with Chronic Idiopathic Constipation”

           Co-Principal Investigator

           Funding organization: Synergy Pharmaceuticals

           Starting date: October 2014


 “A Double-Blind, Placebo-Controlled, Parallel-Group, Multicenter, Multiregional, One Year Study to Assess the Efficacy and Safety of Twice daily Oral Rifaximin Delayed Release Tablets for Induction of Clinical Remission with Endoscopic Response at 16 Weeks Followed by Clinical and Endoscopic Remission at 52 Weeks in Subjects with Active Moderate Crohn’s Disease”

      Co-Principal Investigator

      Funding Organization: Salix Pharmaceuticals

      Starting Date: April 2015


“A Multi-Center, Randomized, Open Label, Controlled Study to Investigate the Treatment Response of Intravenous Injectafer® (Ferric Carboxymaltose) vs. Oral Iron to Baseline Hepcidin Levels in Patients with Iron Deficiency Anemia(IDA) secondary to Inflammatory Bowel Disease(IBD) or Gastric Bypass.”

Co-Principal Investigator

Funding Organization: Luitpold Pharmaceuticals, Inc.

Starting Date: April 2015


“An Open-Label , Long-Term Safety and Tolerability Study of Plecanatide in Patients with Chronic Idiopathic Constipation (CIC)”

Co-Principal Investigator

Funding Organization: Synergy Pharmaceuticals

Starting Date: October 2015

Select Honors & Accomplishments:

  • Castle Connolly Medical Ltd. "Top Doctors", 2016-2018
  • Fellow, American College of Gastroenterology

Select Publications:

Research Networking Profile