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Dr. Karl Mersich

Dr. Karl Mersich

Dr. Mersich: Dr. Mersich is board certified in gastroenterology and bring over 25 years of gastroenterology experience to take care of patients of GGO, where he takes pride in providing compassionate, patient centered care.

His interests involves all areas of gastroenterology and hepatology, including inflammatory bowel disease (Ulcerative colitis, Crohn’s disease), prevention of colon cancer, treatment of colon polyps, gastroesophageal reflux disease, Barrett’s esophagus, peptic ulcers, celiac disease, irritable bowel syndrome, diseases of the pancreas, hepatitis/Hep C and liver cancer.

Dr. Mersich considers himself blessed by his loving wife of 43 years and by his growing family, having 4 married children and 8 grandchildren. He loves spending time with his wife, his family as much as possible, loves traveling, volunteering and good food.


Medical School: Semmelweis Medical University
Residency: St. Mary’s Hospital/University of Rochester
Fellowship: St. Mary’s Hospital/University of Rochester


  • Gastroscopy
  • Colonoscopy with removal of polyps
  • Dilatation of strictures
  • Investigating and treating GI bleed
  • Capsule endoscopy

What our patients are saying:

  • Dr. Ahmed and staff are welcoming, accommodating and professional.

  • First time here, great staff from start to finish.  This was my first procedure with Dr. Shamoun. He really knows what he’s doing.

  • Very pleased with Dr. “V” and staff

  • I know feel better than I have in years

  • After having been to 3 other GI doctors I was ready to give up hope.  Dr. Gupta was very nice, explained my problems to me in 1 visit and came up with a great treatment plan.  I know feel better than I have in years!!

  • "I went to see Dr. Gupta for the first time after Dr. Mari sent me to him. I have been suffering from stomach pain and arthritis and have been hospitalized 3 times over the past 2 years for this with no answer. He said he was concerned about Crohn's disease and diagnosed me with this 2 days later ...Read More

  • "Blood in my stool prompted me to have a colonoscopy done by a surgeon and was told I would need to have half my colon removed because of pre-cancerous plops. The outlook for me was bleak, diarrhea, colostomy bag were some of the possible outcomes of a partial colon removal. After talking to my ...Read More

  • "A superior doctor/surgeon = very intelligent, very knowledgeable, kind and caring... Admire this doctor very much... Would recommend him to anyone for anything!!!!...I have had several surgeries by Dr. Gupta - all total painless!!!!!!!... very competent - thorough!!!!!... A great doctor!!!!!"

  • "After many years of suffering from hemorrhoids, Dr. Gupta solved the problem in a very quick and painless way. He used a new ligation system that eliminated the hemorrhoids in three visits. During the visits, Dr. Gupta treated me with care and patience, for which I am very thankful."  

  • "Dr. Gupta is a kind and humble man who truly listens to his patients. He makes quick and accurate diagnoses, and confined to monitor me until I was fully recovered. During a very trying time, I found him to be comforting, and he helped me maintain a positive outlook. Great doctor!"

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