Welcome to PREMIER GASTROENTEROLOGY INSTITUTE (PGI), Your Board Certified Gastroenterologists in The Inland Empire of California.

Welcome! The gastroenterology professionals at Premier Gastroenterology Institute are pleased to welcome you to our practice. We want all our patients to be informed decision makers and fully understand any health issues you face. Our skilled gastroenterologists provide expert care for conditions like IBS, Crohn's, GERD, and other digestive issues. Explore our site for information on what to expect during your colonoscopy, or endoscopy, and more.

Our website also provides you with the background about our gastroenterologists, staff, office hours, patient forms, prep instructionsappointment procedures, maps, directions to our office and other useful information. We know how hectic life can be and are committed to making our practice convenient and accessible. And we want you to feel confident that when you choose our practice, you're working with professionals who are qualified, experienced and caring.

Please take a few moments to look through this site to get a better feel for the capabilities and services of our Gastroenterology office. We also invite you to email or call our office at any time to request an appointment or ask any questions. Thank you.

Premier Gastroenterology Institute
Book Online
Now offering video visits!
See available times and book
an appointment right here.
It's free, fast and secure.


Meet the founder of PREMIER GASTROENTEROLOGY INSTITUTE Dr. Deborah Negusse, M.D., M.P.H.

HARVARD UNIVERSITY and USC trained/Board-Certified

  • Founder of PREMIER GASTROENTEROLOGY INSTITUTE, Deborah Negusse, M.D., M.P.H.

    Deborah Negusse, M.D., M.P.H.

    Rancho Cucamonga, San Bernardino & Riverside, CA, Founder & Board-Certified Gastroenterologist

    Premier Gastroenterology Institute

    Dr. Negusse was raised in Southern California.  She obtained a joint Master of Public Health and Doctor of Medicine degree from  HARVARD UNIVERSITY AND UNIVERSITY OF SOUTHERN CALIFORNIA.  She then completed a Gastroenterology and Hepatology fellowship at Loma Linda University following her internship and residency at the University of Southern California. While in private practice, Dr. Negusse remains a Clinical Assistant Professor at Loma Linda University.  As a Board-Certified Gastroenterologist, she focuses on various aspects of gastroenterology including hepatobiliary disease, digestive diseases, pancreatic diseases, inflammatory bowel diseases, and colon cancer screening.  She is very experienced in endoscopic procedures for both diagnostic and therapeutic purposes. 

    She is well known for her expertise in gastroenterology and her excellent bedside manners.  She believes in patient centered care, compassion, and attends to the individual needs of patients.  She is fluent in Spanish and is one of the only female Spanish speaking Gastroenterologists in the Inland Empire. 

    During her free time, she enjoys running, swimming and quality time with her husband and two children.  

Testimonials and Reviews

    5 STAR*****

    I was referred to Dr. Negusse from my PCP at Carbon Health and I am so happy I went! Having a family history of colon cancer, I knew I had to get checked out at a younger age. I went in nervous as I’ve never had a colonoscopy before but the front staff and doctor were so nice. We went over what would happen and scheduled my appt. She is super thorough and talks you through each step of the way. The actual procedure went by super fast and my follow up was good as well. I’ll see you in 5 years Dr. Negusse!

    Christina Wong

    5 STAR*****

    I absolutely love Dr. Negusse. I would highly recommend her to anyone in need of a Gastroenterologist. She is very knowledgeable and takes the time to talk with her patients and does not just rush through to the next patient. She is very compassionate and generally cares about her patients quality of care. Her staff is very caring and considerate of patient's time. Corrine is a breath of fresh air when it comes to patient care. She puts patient's anxieties at ease. Daisy is new to the office but definitely a solid light in the office.

    Lydia Davidson

    5 STAR*****

    She is the best doctor I have ever seen. Her staff is amazing. The best one is her manager Corinne, she helped me thru everything and I recommend this office to EVERYONE I KNOW


    5 STAR *****

    I’m so thankful I found Dr.Negusse . Dr.Negusse used to practice with Dr.A. The only reason I would return to Dr.A office is because of Dr.Negusse but when she opened her own practice I immediately knew I had to follow Dr Negusse . She is not just any doctor she is a Mother , a friend , a great person who I know I can trust her with my life and my families as well . She has done all of my procedures and has helped me with my colon cancer family history . She has helped my siblings and I stay in great health . Dr Negusse has gone above and beyond for me . I recomendable her tremendously to anyone who needs a gastroenterology. Thankyou Dr Negusse for loving your patients and treating us like family .

    Daniela Michaelson

    5 STAR ****

    Outstanding doctor. Listens, cares, and takes her time with you. She thoroughly explained the colonoscopy procedure so I was prepared and comfortable. After my procedure she went over the findings and followed up afterwards with additional results and answered all of my questions without rushing me. She is calm and professional and I feel that I have had the best care. I trust Dr. Negusse with my GI needs and highly, highly recommend her.
    April Taylor

    5 STAR ****

    Dr. Negusse is amazing! The high level of care she provides and her exceptional bedside manner makes me wish she could be my primary care physician! She is thorough and makes me feel like I’m her only patient!
    David Wakefield

    5 STAR ****

    Wow must I say wow . I have never been at a doctors office where the office is so clean and efficient and friendly . When I walked in the door I was greeted by the nurse Daisy who is very friendly and helpful , she checked me in and assisted with any questions I had . I sat down and immediately the manager Corrine came and greeted me and took me back to the exam room and asked very thorough and information questions she was amazing and very helpful and patient with me . About 2 minute wait time ! It was great . The doctor came in right after and we talked for a while and reviewed and assessed my health. She walked me through the process of how my procedure would be and took the time to speak to my wife and I about our concerns. After we left we called the office because my wife was so impressed she wanted to be seen . Dr Negusse was able to see her the same day . The staff is amazing and treats us like persons and not just like patients . I’m looking forward to going back to the office and seeing everyone .
    Mathew Gomez

    5 STAR *****

    Negusse was wonderful. She walked me through every step of my first colonoscopy and what to expect before and after. She was professional and answered every question I had prior to and just before the anesthesia was administered. She explained everything after the procedure, what was found and reviewed every picture she took during the procedure to ensure my complete understanding. I highly recommend Dr. Negusse and will return to her for my next procedure.


Contact Us

Send Us an Email

Our Locations

8221 Rochester Avenue Suite 130, Rancho Cucamonga, CA, 91730

Hours of Operation

Our Regular Schedule



9:00 am-5:00 pm


9:00 am-5:00 pm


9:00 am-5:00 pm


9:00 am-5:00 pm


9:00 am-5:00 pm