Our top priority is offering support for you and your family from diagnosis through recovery, so you know what to expect at every stage in your journey. Our gastroenterology team of board-certified physicians treat gastrointestinal conditions and liver disease with state-of-the-art technology and follow recommendations from the American Society of Gastroenterologists Association, ASE, American Society of Endoscopy and American College of Gastroenterology in delivering care. It helps us find better answers – and provide effective treatments – for your GI concerns as soon as possible.

Conditions We Treat

Our team is here to provide the care and close attention your gastrointestinal condition deserves. We encourage patients to ask any questions they have, as it helps our providers find answers that everyone can feel confident in.

Abdominal Pain/Lower GI Tract

  • Change in Bowel Habits
  • Colon Cancer
  • Colon Polyps
  • Constipation
  • Diarrhea
  • Diverticulosis/Diverticulitis
  • Irritable Bowel Syndrome

Abdominal Pain/Upper GI Tract

  • Barrett’s Esophagus
  • Esophagitis
  • Gastritis
  • GERD/Reflux/Heartburn

Colitis: Microscopic, Infectious Celiac Disease

C-Difficile/Fecal Transplant

Cyclic Vomiting Syndrome (CVS)


  • Achalasia
  • Dysphagia
  • Esophageal Dysmotility
  • Gastroparesis
  • Motility Disorder

GI Bleed

  • Anemia
  • Hematemesis
  • Hemorrhoids
  • Peptic Ulcer Disease
  • Rectal Bleeding


  • Ascites
  • Cirrhosis
  • Fatty Liver
  • Hepatitis: Autoimmune, A, B, and C
  • Portal Hypertension/Esophageal Varices
  • Primary Sclerosing Cholangitis
  • Primary Biliary Cholangitis


Inflammatory Bowel Disease (IBD)

  • Crohn’s Disease
  • Short Gut Syndrome
  • Ulcerative Colitis/Proctitis


  • Bile Duct Stones
  • Acute/Chronic Pancreatitis
  • Peg Placement

Treatments and Procedures

Using state-of-the-art, high-definition scopes, our gastroenterology team performs many minimally invasive, endoscopic diagnostic tests and procedures for more efficient and effective treatment.

  • Breath test (lactose intolerance)
  • Colonoscopy
  • ERCP
  • Fecal transplant
  • Flexible sigmoidoscopy
  • Gastroscopy
  • Hemorrhoid banding

Our Doctors

As members of the community themselves, Froedtert South Medical Group physicians are dedicated to making GI care and treatments readily available to our neighbors here in southeastern Wisconsin.

Mario Garretto, M.D.
Mario Garretto, M.D. Gastroenterologist
Phillip Chung, M.D.
Phillip Chung, M.D. Gastroenterologist
Andrew Mazulis, M.D.
Andrew Mazulis, M.D. Gastroenterologist
Thomas Wagner, M.D.
Thomas Wagner, M.D. Gastroenterologist


Map of Prairie Ridge Clinic
Prairie Ridge Clinic

9697 St. Catherine's Drive
Pleasant Prairie, WI 53158

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Phone Numbers