The care provided at Associated Gastroenterology Medical Group was phenomenal. All staff…read more(Receptionist, Nurses, Anesthesiologist, and the Doctor) were extremely supportive, knowledgeable, friendly, and professional. Overall, I absolutely would not hesitate to recommend AGMG to anyone needing their services.

Dr. Riff is an excellent physician with outstanding bedside manner. I've been a patient since 2020…read moreand have always trusted and appreciated the care I've received from him. Unfortunately, my recent experience with the office's a staff from their billing department was extremely frustrating and unacceptable. I was blindsided by a past-due bill after two years with no prior notice. When I called to make a payment and understand the delay, I was told that multiple statements had been mailed and voicemails left--none of which I ever received. What was most concerning was the conduct of the billing representative.( I have the name but, not mentioning here) When I calmly asked for an explanation as to why I was being notified after such a long delay, she became defensive, raised her voice, and spoke to me in a disrespectful and aggressive manner. She even threatened to send the account to collections--despite the fact that no such action had been taken during the past two years while the balance was apparently outstanding. This kind of behavior is completely inappropriate and unacceptable, especially in a healthcare setting. When I questioned her tone, the situation escalated further. I was eventually transferred to a supervisor, who took my payment and presented herself professionally; however, the explanation provided still did not justify the delayed billing or the way the situation was handled. While I hold Dr. Riff in very high regard, this experience with this associate with the billing department has severely impacted my overall trust in the practice. No patient should be treated this way. Unfortunately, this has led me to seriously reconsider continuing my care here.

i had a referral from my primary care physician for dr. mcquire, as i had used him before for my…read moreproblems. upon getting the referral from my insurance in december, i called for an appointment. they could not see me until march 17th. i didn't ask any questions, as his staff and i have had issues before, i accepted appointment. on march 16th i received a phone call from "robbie" one of his office girls. she left me a message of what i have been diagnosed with and told me i have the wrong doctor..so she apparetly overrides my primary care doctor attempting to get me help wih my stomsch issues, she is fully aware i was his patient but cancelled my appointment andcsaidvto see a rhumatodologist..which i already have. referrels do not state your diagnosis but only the referring to the doctor referred to. ribbie at one puntbwhen my doctor was on vacation and refused to get my percsription for xanex refilled and i had to fight. xanex is a scary drug and i had been takng it for 2 years. the doctor i was using came back and refused my refill. prescribed a medication that should not have had as does not mix well with other prescriptions, thus rendering me extremely ill for several weeks. this revenge attitude is not something that one should not have to put up with. she works there as customer service and her liking or disliking a patient should stay at home. i am filing a complaint with my insurance, the state health departmentv against the dr. license.

Dr. McGuire has performed endoscopies and colonoscopies on all four of us. He, unfortunately,…read morediscovered colon cancer in my late husband and eldest son. He was instrumental in the treatment of my husband and referred my son to the City of Hope. His professionalism is excellent as are his skills. In addition, he genuinely cares about his patients. There is nothing impersonal about his care. I do not say lightly that I trust him with my life. No, he doesn't walk on water. Among all the physicians I've been exposed to he is what I would call the best. How many doctors take time out of their schedule to attend a Celebration of Life Service for a 32 year old patient who lost his battle with colon cancer?

Hepatitis C Dr…read moreChapman was my Gastroenterologist for over 30 years. He always listened to my concerns. He always went over my results from medical tests and explained the numbers. My Hepatitis C was stable and clear in June 2018. He is a great and compassionate Doctor and I will always appreciate him. The office staff are very nice and helpful.

The doctor seem to be very knowledgeable. The staff on the other hand is so overworked their…read moreworkload they can't handle so if you're needing anything urgent definitely go find another office. I have a referral that was approved six months ago and I still haven't gotten the appointment scheduled for my procedure glad it's not too urgent.

Dr. Mortensen helped me a lot with my health over the years. After years of debilitating pain and…read moresuffering he uncovered the root of my ailment and helped me on my journey to achieving optimal health.

I started seeing Dr. Craig Mortenson around November of 2024. I was having all kinds of weird…read moresymptoms and my body was all out of wack. My blood pressure and cholesterol was up, my hormones were down, and I was having weird panic attacks that I've never had before. After trying a few things that made me feel better but not great, my test results came back as having leaky gut in March of 2025. He asked me to get on a strict protein diet and gave me a few supplements, after about 3 months I was feeling better but still had to maintain my diet and supplements and now at month 5 I'm feeling great again and all my tests are stable. When my primary physicians only prescribed me medication to mask the symptoms Dr. Mortenson dug deep to find out what was causing these issues. I am still on the journey of healing my gut and stabilizing my gut bacteria but I can honestly say I feel much better and almost back to normal. I will never regret making the decision to call Dr. Mortensons office and don't even know how I would function if I just gave in and took the meds my primary was giving me and thought that was all that could be done. This team is amazing and you should never just settle with your health!

I can't say enough good things about the nurses, anesthesiologist, and doctors at this center…read more Everyone took the time to explain the process clearly and made sure I felt safe and comfortable throughout. Their kindness and professionalism truly stood out -- from check-in to recovery, the entire staff was amazing! Special Thank Yous to: Callista & Tania! P. Romero Patient

Brought a family member here for a procedure and had a great experience overall. Naina at the front…read moredesk was so great at communicating every detail we needed to know beforehand. And nurse Diane was so helpful and communicative post procedure as well. My loved one felt in good hands and received great care at this facility. It's an older building but very clean and the staff are efficient. 5/5 for professionalism and bedside manner from all the staff. Thanks!

I recently went to see Dr. Yoo for a colonoscopy. I found him through my insurance company website…read moreand saw that he was located nearby in Rowland Heights. When I called to make my appointment, I found out that Dr. Yoo moved his practice to a new building in Diamond Bar as of March 2024. Dr. Yoo's new office is located in the newly renovated Diamond Bar Medical Plaza, which was previously a Chuck E. Cheese (if you all were in the area when that was around). Looks like they are still in construction, as a couple offices are still vacant with plastic on the glass windows. The staff I encountered all very friendly and nice. Dr. Yoo was professional and clearly explained the process and indicated what I needed to do to prep for my procedure. I came in on a Monday and the front staff was able to fit me into an appointment on Thursday due to a last minute cancellation. This kind of procedure is not fun, but the entire staff made me feel comfortable the entire time, and the nurse who attended to me was so nice, I felt like my mom was taking care of me. =) She made sure I had extra blankets because I was cold and came by a couple times to made sure my IV was ok. I got a call the day after to follow up and see how I was feeling and if I was experiencing any issues. I appreciate the check in even though I was feeling good! I highly recommend Dr. Yoo if you need an gastroenterologist.

I want to thank Dr. Sung J Yoo for his amazing medical practices. I went in on October 5th 2023…read morefor a procedure and Dr. Yoo and his entire staff "took great care of me". Including, but not limited to Kim, Michelle, Susan and Angel. I really appreciate how everyone "really cared for me". I also received a "nice follow up call the next day".

Last time I checked doctors need to physically exam patients in order to properly diagnosis. So you…read morecan imagine my surprise that Dr. Matthews isn't seeing patients and will only do phone calls. I've currently been on hold for 15minutes!! Oh and did I say they NEVER called to share test results done over a month ago. Let me save you time and energy, don't pick Dr. Matthews. Well at this point don't pick St.Judes

DO NOT SEE DR. SCOTT SAINBURG!!…read more Completely rude and judge-mental. I was admitted to the ER prior and the doctors wanted a GI to do tests and look at me. He refused to do any test. Refused to look at the medical records. Claimed the ER doctors know nothing and it would be useless to look at their findings. Then he did nothing but lecture me on life. The whole time looking me straight in eye with a smirk, like he was waiting to see my reaction. Like he enjoyed it. Not only was he rude and unprofessional, he kept asking questions about my personal life totally unrelated to the medical conditions. I have filed a complaint with the office manager, my insurance, as well as my primary physician. I'm hoping to stop anyone from seeing him until he gets treatment or changes his behavior. He did nothing to help nor did he even try.

I write this review with immense gratitude for dr. Patel. After being very sick for several months…read moremy symptoms became increasingly worse and debilitating. Not knowing where to turn or whom to trust, thankfully a dear friend referred me to Dr. Patel. During my first appointment, Dr. Patel listened carefully to my concerns and understood that I was not only in severe pain but also nervous about being in a doctor's office. She quickly put me at rest with her compassionate and positive bedside manner. After her very thorough examination, she scheduled multiple tests. These tests identified serious but treatable GI issues, a hormonal imbalance, and a large ulcer that I was completely unaware of. Within a short time after starting treatment I was a newer better version of myself. Now, months later, I continue to improve and truly appreciate Dr. Patel for her incredible ability and willingness to address my medical issues.

After suffering with a very difficult bout of IBS for 10 weeks and not getting answers or help from…read moretwo doctors, I found Dr. Patel, who gave me LOTs of HOPE, along with important information re: my health problems, meds and supplements. She understood how exhausted I was and showed me warm caring as well, which I appreciated! The endoscopy she suggested went very smoothly, with her by my side to answer my questions, beforehand and afterwards. Since my two visits, I've called her office with questions to her medical assistant, Precious, and I received answers from Dr. Patel within a day as well as a personal reply from her via email. Though she is listed here with a Tustin, CA office, she has a Mission Viejo office as well--it's very convenient for me!

I had my initial consultation with Dr. Hardeep Singh about a week ago and was incredibly impressed…read moreby his excellent bedside manner and utmost professionalism. The front office made the entire process incredibly seamless, and I was able to secure an appointment within just one week. They provided crystal-clear instructions for my colonoscopy prep, which I completed the day prior. The procedure itself took place at a convenient facility just down the street. Although they were quite busy on the day of my procedure, resulting in a slightly longer visit, the efficiency, care, and dedication of the entire team were outstanding. They are a highly professional and compassionate group, and I highly recommend them. Thank you so much to Dr. Singh and his wonderful staff!

Dr. Singh is very professional, thorough and made me feel very comfortable for my procedure.read more