Pediatric Gastroenterology

The Pediatric Gastroenterology, Hepatology and Nutrition Practice at Valley Children’s specializes in the diagnosis and management of infants, children, adolescents and young adults with complex and common gastrointestinal and nutritional disorders. Led by Dr. Marvin Ament, one of the founders of pediatric gastroenterology in the United States, the practice provides the most comprehensive pediatric gastroenterology services in Central California. 

The practice treats many conditions such as: 

  • Acute and chronic abdominal pain
  • Esophageal reflux
  • Acute and chronic infectious and noninfectious gastritis
  • Gastrointestinal bleeding
  • Reflux esophagitis and allergic esophagitis 
  • Acute and chronic liver diseases 
  • Irritable bowel syndrome
  • Ulcerative colitis, Crohn’s disease, and unclassified inflammatory bowel disease 
  • Acute and chronic constipation 
  • Acute and chronic pancreatitis 
  • Acute and chronic gall bladder disease (with and without stones) 

If tests are needed, the practice provides a full range of diagnostic and therapeutic options in our state-of-the-art endoscopy and motility unit to ensure the best care for young patients. 

Team Approach

Our expert team includes nurse practitioners, nurses, dietitians, child life specialists, social workers and psychologists who focus on treating the whole child in collaboration with our pediatric gastroenterologists and other pediatric specialists. This team approach enables us to deliver the highest level of individualized care and treatment to diagnose – and solve – even the most difficult conditions. The practice sees about 14,000 outpatients a year at locations throughout Central California to provide care to children and families close to their homes. 

Focused Centers of Care

Our pediatric gastroenterologists oversee focused centers of care to provide a full spectrum of care, utilizing minimally invasive procedures whenever possible: 

  • Advanced Endoscopy
    • Endoscopic ultrasound (EUS)
    • Endoscopic retrograde cholangiopancreatogram (ERCP)
  • Motility Center 
    • Anorectal
    • Esophageal
    • Colonic Manometry
  • Inflammatory Bowel Disease 
    • Short Bowel
    • TPN
    • Feeding Disorders
  • Spina Bifida: Coordinates care with the Spina Bifida Center at Valley Children’s Pediatric Urology Department.
  • Liver Disease/Transplant: Treats liver disease and follows liver transplant patients in a combined clinic with Stanford University School of Medicine. 
  • Weight for Life: Uses a multidisciplinary approach (pediatric gastroenterologists, interventional gastroenterologists, dietitians, psychologists, etc.), resting energy expenditure (REE) calculations, and more to help children with comorbidities due to obesity. 

A pediatric gastroenterologist is on-call 24 hours a day for consultations and emergencies. 


McHenry Specialty Care Center, Modesto
Olivewood Specialty Care Center, Merced 
34th Street Specialty Care Center, Bakersfield 
Akers Specialty Care Center, Visalia
Sierra Vista Regional Medical Center, San Luis Obispo

Pediatric Gastroenterology Referral Guidelines


Our Specialists

Marvin Ament, MD

Karla Au Yeung, MD

Michael Finch, MD

Roberto Gugig, MD

Syed Hamid, MD

Clifton Huang, MD

Philip McDonald, MD

Minesh Patel, DO

Anita Sicolo, MD

Joshua Warolin, DO

William Berquist, MD

Ricardo Castillo, MD

Kenneth Cox, MD

Melissa Hurwitz, MD