Book Appointment
I see patients at the following locations:
Wantagh North
Wantagh South
Education
Bachelor’s Degree – Binghamton University
Medical Degree – American University of the Caribbean School of Medicine
Internship – Winthrop University Hospital
Residency – Winthrop University Hospital, Chief Resident
Fellowship – NYU Winthrop Hospital
Board Certifications – Gastroenterology, Internal Medicine
Hospital Affiliations
- NYU Langone Hospital – Long Island
- Mount Sinai Hospital
- Mercy Medical Center
Fun Facts
Dr. Marshak is an active member of the American College of Gastroenterology. He is a diplomate of the American Board of Internal Medicine and is board certified in both internal medicine and gastroenterology. He is published in multiple peer-reviewed medical journals. He has also given presentations at both national and regional medical conferences.
Dr. Marshak lives on Long Island with his wife and daughters. He is an avid sports fan who enjoys hockey and football.
Conditions & Diseases Treated
- Abdominal Pain
- Achalasia
- Acid Reflux
- Bacteria and Foodborne Illness
- Barrett's Esophagus
- Celiac Disease
- Chronic Diarrhea
- Clostridioides Difficile
- Colon Cancer
- Colon Disease
- Colon Polyps
- Colorectal Cancer
- Constipation
- Crohn’s and Ulcerative Colitis
- Diarrhea
- Difficulty Swallowing (Dysphagia)
- Diverticulosis/Diverticulitis
- Esophageal Cancer
- Esophagitis and Stricture
- Fatty Liver
- Fecal Incontinence
- Gallbladder Disease
- Gallstones
- Gas
- Gastric Cancer
- Gastritis
- Gastrointestinal Malignancies
- Gastroparesis
- GERD
- H. Pylori and Peptic Ulcer
- Heartburn
- Helicobacter Pylori/Peptic Ulcer
- Hemorrhoids
- Hepatitis A
- Hepatitis B
- Hepatitis C
- High-Risk Colon Cancer Screening
- Inflammatory Bowel Disease, Including Crohn’s Disease and Ulcerative Colitis
- Iron Deficiency Anemia
- Irritable Bowel Syndrome
- Jaundice
- Lactose Intolerance
- Laryngopharyngeal Reflux
- Liver Cirrhosis
- Liver Disease
- Nausea and Vomiting
- Nonalcoholic Steatohepatitis (NASH)
- Obesity
- Pancreatic Cancer
- Pancreatic Cysts
- Pancreatitis
- Peptic Ulcer Disease (PUD)
- Primary Biliary Cirrhosis
- Proctitis
- Rectal Bleeding
- Rectal Cancer
- Reflux Esophagitis/Stricture
- Silent Reflux
- Stomach Ulcers
- Swallowing Difficulty
- Ulcerative Colitis
Procedures Performed
- Bacterial Overgrowth Test
- Capsule Endoscopy
- Colonoscopy
- Diagnostic & Therapeutic Colonoscopy
- Diagnostic & Therapeutic Endoscopy
- Esophageal Dilation/Testing
- Flexible Sigmoidoscopy
- Flexible Sigmoidoscopy and IRC
- Hemorrhoid Infrared Coagulation Therapy
- Hemorrhoid Treatments (IRC and Banding)
- Lactose Intolerance Breath Test
- Upper Endoscopy
- Upper GI Endoscopy (EGD)
- Urea Breath Test (UBT)
- Variceal Banding
