Most personable staff I've ever experienced. Clean, organized, and welcoming office. Quality care and service.

RIPOFF! Do Not trust this Doctor. I do not owe the Advanced Digestive Center of Southern California any money, yet they have sent a collections agency demanding I give them money! When I left their office many years ago, my balance was zero. Me and my Insurance Company have paid all there is to pay to the Advanced Digestive Center of Southern California. We have paid every bill and co-pay on time and in full. I have called their billing department to clear things up but the billing representative gave me incorrect information and started listing days, times and procedures that I had never been a part of. I told her she was terribly mistaken that her information was incorrect. I also told her my balance was Zero. She said ok, someone would call me back, but they never did. After reading their YELP reviews, I noticed their billing department has great difficulty with billing their clients correctly. I can see from their Yelp reviews that many, many people have the exact same complaint that I do: billing for no reason, billing incorrectly, etc. Also their employees are terribly rude to customers and could care less about everything, especially YOU. I think it is terrible this company does this same thing to other folks. Like I said, I do not owe this company any money. read more

Dr. Simoni and Fernanda are wonderful clinicians...excellent bedside manner, great listeners, and so kind! I will be recommending this office to my friends and family as well. Top notch care! read more

Care is quick and easy. Staff is courteous and helpful. Was in and out so darn quick today for my FibroScan. Thank you!!!

Friendly staff, reliable, great experience. The GI doc, ultrasound tech, front desk staff, and nurse practitioner are all really friendly and helpful read more

Everything went easy , smooth and well after my first call to the office and spoke to Cermina, she did everything fast and finally at the visit time Zoe did professional and friendly service for me. Thank you all read more

Dr Simoni and is staff are amazing! The staff are very friendly, kind and professional. Dr. Simoni is great! He listens to you, takes time to answer questions and explain everything, and is a caring doctor! I highly recommend Dr Simoni and staff! read more

Bait-and-switch! I jumped through all the hoops-- uploading my previous records and filling out the forms before they would even schedule an appointment. Then I drove past dozens of gastroenterologists between Santa Maria and Thousand Oaks to see Dr. Simoni. If I had read his Yelp reviews prior to making the appointment, I probably would have gone elsewhere. I went to all that trouble for one reason: His website prominently features Trans Nasal Endoscopy and Wireless Capsule Endoscopy. I have struggled with recurring bouts of anemia, and I wanted to rule out gastrointestinal bleeding, but I didn't want to have another upper endoscopy, and I can't have a colonoscopy due to an anatomic anomaly that prohibits passing a scope through my intestines. I brought a bullet point summary of my history and my reason for being there, which I wanted to go over with the doctor. When I mentioned it to his medical assistant, she offered to scan it into my record. I agreed, but I asked her to bring it back, so I could go over it with the doctor. Instead, she gave it to Dr. Simoni's PA and she and Dr. Simoni apparently read and discussed it before he came into the exam room. That IS NOT what I asked her to do! When Dr. Simoni came in, he quickly shot down both Trans Nasal Endoscopy and Wireless Capsule Endoscopy (which is lauded on his website for the ability to detect bleeding in the small intestine). Instead, he insisted that I needed another upper endoscopy and a colonoscopy. I explained why I didn't want to have an endoscopy and why I couldn't have a colonoscopy, and he basically said that my other gastroenterologists were incompetent and he could do it. Navigating a tortuous colon is very difficult and carries a higher risk of perforation, which is why most gastroenterologists won't attempt it. Note that under the best of conditions, the perforation rate of upper endoscopies and colonoscopies is 1 in 100, and of those, 25% are fatal! That means your risk of dying from one of those procedures is 1 in 400 (and a friend of mine nearly did)! I'm guessing the odds are even worse with an arrogant, overconfident doctor. At one point, he asked me if I ever had canker sores. I replied, "Once in a while." He said, "You have Crohn's disease." I DO NOT have Crohn's disease! (I have NO Crohn's symptoms.) My canker sores are caused by a dormant virus that surfaces if I eat too many nuts, thanks to an arginine/lysine imbalance. Malabsorption CAN cause a B12 deficiency and result in canker sores, but my B12 level is fine. He never asked. I feel like I was duped by a bait-and-switch tactic! The promise of those alternative procedures lured me in, and then he attempted to "upsell" me by insisting on a much more costly and risky plan. As other reviewers have mentioned, Dr. Simoni seems to be all about the money. He won't accept you as a patient until he sees your records. I'm guessing he saw mine and thought I was not only good for an endoscopy and a colonoscopy, but possibly a TIF procedure for my hiatal hernia and a cholecystectomy (gall bladder removal) referral, as well. He also accused me of spending too much time with "Dr. Google." Yes, I absolutely do research my conditions and learn about them online! I wonder why Dr. Simoni has a problem with well-informed patients? My advice would be to avoid this practice. read more

BEWARE! In July 2019 at the age of of 58 and in great general health I started experiencing heartburn about an hour after meals. I was referred to Dr. Gilbert Simoni. I liked him and he seamed very concerned. At my first visit and after his thorough examine he stated, "I have no idea what could be causing this." So we began a 6-month ordeal of him ordering $20,000 to $30,000 of every possible Gastrointestinal test under the sun! After 6-months of negative test results and billing me $20,000 - $30,000 he suggested I might have a simple Gluten Sensitivity. He then suggested I eliminate Gluten from my Diet. DAH! I then eliminated Gluten from my diet and within 2-months I was back to feeling 100%. He never did any Blood test during this time including but not limited to the following: wheat IGE test-Gluten Sensitivity-Cyrex Array 4-Antibody Panel. Now for the Topper! In September 2023 I get a call from a collection agency telling me I owe Dr. Simoni (Advanced Gastroenterology) $1,799.74 from a $4,000.00 Upper GI Scope in 2019. Ready for this one...The bill sates I owe the $224.74 (or so the bill explained for a percentage that my Ins did not pay. THE TOPPER HERE IS I OWE $1,575.00 IN LATE FEE'S!!!!!!!!! At this point I have reached out to the California State Attorney Generals office. At the very least this seems to be an issue concerning the (FDCPA) Fair Debt Collections Practices Act. read more

dr Simoni of advanced G.I. medical has provided me with the most outstanding medical care . His medical knowledgeable is exceptional. , I have great comfort in his remarkable bedside manner: highly perceptive, compassionate, astute, and very efficient. His team/ staff are most helpful, courteous, and efficient. overall experience is outstanding read more

I first saw doctor Simoni after seeing multiple GI specialists that dismissed me after not being able to diagnose my stomach pain. Dr. Simoni immediately recognized errors in my previous testing and ordered new and more comprehensive tests. Soon after, Dr. Simoni discovered I had been infected with a bacterial virus that affects the small intestines. He is currently still continuing to test me for other possible reasons for inflammation. Dr. Simoni is very thorough and is determined to get answers for my pain. His staff is also wonderful and are able to answer any questions I have in an efficient manner. I highly recommend Dr. Simoni to anyone with GI symptoms. read more

Wow! Everyone was so nice & professional. I had a colonoscopy done by Dr. Simoni. It was over so quickly. I highly recommend him for all gastronomy procedures. read more

Even though I was late in arriving for my appointment. I was seen within 15 minutes of arriving. Dr S listen to all issues and front desk was nice read more

What an amazing awesome GI Specialist! Dr Simoni is not only a professional, skilled, experienced specialist, he's also a very caring and kind-hearted human being! The staff are professional and efficient and caring! I give Dr Simoni my highest recommendation! He is a knowledgeable and marvelous physician! J. Dender, MD Encino read more

Great and friendly staff. The doctor is nice and it is really easy to communicate with them. You can call, text, or email and they respond pretty much right away. The office is also really nice and they do everything in house. I highly recommend them. I've been with Dr Simoni since 2009 and drive all the way from Palmdale for my visits. read more

Beware. Costs are astronomical. Do not use this office if your insurance doesn't cover. There are other doctors out there to choose from.

I had my first ever Fibroscan today and let me tell you, the office personnel are very professional, courteous, and caring! I didn't know what to expect and Traci was very informative and patient with me and my concerns. The process was super easy, painless, and quick. I got the results the same day. Hats off to Dr. Simoni and his entire Staff! I recommend Dr. Simoni for sure! Thank You, Jeff C. read more

Disappointing the way that they conduct business. Office staff are very rude called four days in a row they always said that they will call me back and they never called me back and didn't take the time to go over the procedure beforehand as they said they would I feel like they really didn't care so unprofessional was the office staff an extremely rude read more

Very professional. On time. Saw me right away. Answered all my questions. I had a great experience 7 years ago and that's why I came back. They scheduled my procedure for two weeks from which fit my schedule perfectly. read more

Welcome to Dr. Gilbert Simoni's Advanced GI practice in Thousand Oaks, where the primary goal of Dr. Simoni's practice is to increase his personal wealth all-the-while ignoring the medical well-being of the patients he so-called serves. Simoni is great at one thing, testing testing and more testing. Yes, on the surface it may seem like excessive amounts of testing in order to find the root cause of an issue is great, but a comprehensive quantitative study will find that the excessive "highly recommended" testing at his Ringling Brothers and Barnum and Bailey practice continues long after certain possible causes to medical issues should have been ruled out. I was a patient of Simoni, but I was often concerned and skeptical about the care I had been receiving. When I sought answers to my concerns, I was overwhelmed with bombardments of conflicting and incompetent reports depending on who in that circus picked up the phone on any given day. On a Monday, for example, we were informed that if a colonoscopy had been conducted within two years, then certain procedures could move forward; but then a call to verify prudent information on a Tuesday would invalidate the previous days findings; then a call on a Thursday at 1:00 PM would lead to a receptionist picking up the phone from home only to state that the office closes at noon and perhaps the infamous "nurse practitioner" who always had less information to provide than a high school student reading a pamphlet for an on-line nursing program, might be able to answer questions that had and hadn't been answered by countless other individuals - but only if I schedule an appointment so that insurance can be billed. Only when push came to shove, the God Of Gastroenterologists would finally reach out, but even then, he too was often confused about what procedures were covered during what timeline and for what purpose. Because my health was (and is) more important to me than what these clowns embraced, during a walk with a neighbor and friend who happens to be a medical doctor himself, I shared my concerns and showed him all the results of all the tests that Simoni had ordered. My friend's first response was, "If they didn't find a pattern consistent with IBD and you don't have Celiac disease, why is this doctor continuing to test you for IBD and Celiac disease?" I didn't have an answer to my friend's inquiry. He added, "It seems to me that you have a gluten allergy." The following morning, I called Simoni's office to ask about why they are continuing with testing. The initial response I received was, "Dr. Simoni does not like his patients seeking a second opinion." This was an immediate red flag. If any doctor wishes that his/her patients not seek additional advice, run! At that moment, I decided to seek a second opinion and change doctors entirely. My wife and I did our research and found another specialist and scheduled an appointment. Once Simoni found out that I talked to a friend about my own personal medical concerns, the God-complex within Simoni exploded and Hades released the Kraken onto the city of Joppa with a barrage of confusing phone calls from an array of members within his circus until eventually, one of his disgruntled employees stated, "Dr. Simoni has decided to cancel your appointment on Tuesday and all upcoming appointments as well." Coward. Was Simoni's sudden domineering and aggressive attitude a form of overcompensation due to other non-related personal issues? The emotionally damaged fragile regime couldn't seem to handle a patient having a friend who also happened to be a medical doctor. Yesterday, I had an appointment with a new Gastro specialist, and after he analyzed all Simoni's findings and asked a bunch of questions, he stated, "Seems to me like you have a gluten allergy." Go figure. read more

Wonderful and professional doctor and staff. Highly knowledgeable and they take the time to provide detailed information and answer questions. Services performed on-site, which is very convenient for the patient. read more

I thought this was a great doctors office until today. I had a test scheduled this morning, had to take off work and be fasting. I have a vestibular disorder and cannot lay flat on my back and while I understand this presents challenges for tests and exams, I have never had a doctor or technician who couldn't work with me and have me a slight inclined position or something to make it work. I've also had other tests done at this office and other techs here made it work. This also that is in my chart with them and not unknown. Today the tech, (who is just a front office staff trained once on how to do this test) said she did not know how to do it unless I was laying flat. So she got another front office person aka tech (Zoe) to come in who was the rudest, most insensitive person I've encountered in an office in a while. She asked me if I've ever tried laying flat as if I don't know my own medical conditions. I made several suggestions on how to do this and she judt shrugged and said we can try but I don't think we'll get very good images. I was upset then and said you must have had to deal with this with other patients, and she said no, I've never dealt with something like this. At that point I asked to speak to the doctor, the office manager or the NP, all of whom were conveniently unavailable. So I grabbed my stuff and went to the front desk to try and talk to someone else, but Zoe followed me and stood behind the front desk and refused to let me talk to anyone else. I told her I wanted a call back from the office manager or the doctor and she said she'd relay the message but couldn't guarantee they'd call back. She then said they would review the surveillance camera and she would tell them I refused the test!!! Surveillance camera?? Like I'm a criminal?? That's how you interact with your patients?? Yes, I was very ipset!upset!! This girl made me feel totally shamed and humiliated and like I was some kind of freak, and offered no assistance in trying to figure out how to complete a needed test. I also said I would be looking for a new doctor and her response was let me know when you find one. Not only will I never go back to this office, nor will my daughter, but I will be looking into filing a complaint with the medical board for THEIR refusal to treat me without being able to exacerbate another medical condition, and for having untrained office staff performing important medical tests. Zoe needs to be fired!! In response to your comment defending the entire process and your office staffs complete lack of empathy, I'm disgusted. She made me me feel like a total freak because I can't lay flat and no, she did not offer any solutions other than to try but likely get poor results. She is the one who was rude and unprofessional and absolutely has no business treating patients. Your office knows that I cannot lie flat, so why was this test ever ordered for me?? Your complete lack of responsibility and defense of this horrible staff members attitude sickens me. I will be filing a complaint with the medical board because I'm sick of doctors and their staff treating people in this manner, refusing to allow them to speak to anyone else, and then defending their disgusting behavior. On top of that, despite all the tests and appts I, nor my daughter have a single diagnosis, answer or solution from you!! Colossal waste of time and money, only to be treated like this in the end. read more

This doctors office is very to the point, very thorough and complete. No messing around. Front desk is helpful, she is one-woman show but knows her job. I have yet to meet the Dr but the nurse practitioner was thorough and took her time to understand. read more

Excellent service. Staff members are friendly, supportive and professionals. My appointment was ontime. Recommend this office to anyone that needs their services. read more

I had a terrible experience with not only Dr Simoni but the entire staff and practice. Fortunately, there are alternative gastroenterologists in the area that do a fantastic job. Unfortunately, I had to spend thousands of dollars, do several tests and be mistreated by the staff before discovering this. Hopefully you won't. read more

He is so pleasant and friendly and caring He takes his time to explain everything in detail His office is so high tech and nice and his staff are friendly Highly recommend him read more

Transparency? Is it a joke? Called back to ask clarification. The office told me they don't know what "has nothing offer" means.

DO NOT COME TO THIS DOCTOR!!! Dr. Gilbert Simoni is a crook, all he cares about is money not his patient. He will try to get money out of your pocket as much as he can by ordering unnecessary tests & put you in front of his staff & nurse practitioner to hear all about your results who by the way are clueless. If I could put 0 star I absolutely would. Please rethink and do more research before you sign up with this greedy doctor!!!! read more

Great staff and really good experience with my most recent colonoscopy. I recommend.

Terrible doctor. Took no responsibility when he perforated my spleen during a "routine " colonoscopy. Doctor and staff unprofessional and insensitive. Would not recommend him read more

The office keeps busy, but well organized. The staff was very pleasant and worked quickly. Dr. Simoni is well-read, knows his field very well, but also a lot about various fields that help supplement gastroenterology. He also has a great memory, which I'm sure comes in super handy since he's a doctor :) The nurses were sweet and super helpful. Overall we had a great experience. read more

I do not recommend this office. The doctor is competent, but unfortunately the front office runs the whole show. Don't question the assistant if you fail to understand something, as they might take offense. Don't ask anything from the front office staff, because they are apparently on edge. They literally have lost perspective that people with real issues are coming into the office and sometimes have other, more serious concerns on their mind. The major issue here is you can established a good/normal/trusting doctor-patient relationship, and BAM ... the front office sends a letter and kills it with no explanation. I guess it is "hurt" feelings. Rather pathetic of them to not address the issues when they happen. Heaven forbid a valid issue might be raised/addressed or a misunderstanding might be cleared. I have a spouse who was a big patient of his and now she will no longer go here. I also have 2 in-laws that we referred to this office over the years, and they also had similar thoughts about their experience with staff. Again, I recommend that you pass on this office. read more

The staff has been amazing. Both the doctors have answered all my questions. DR.Simoni make you feel really comfortable.

Fernanda the NP and Dr Simoni are very knowledgeable and thorough. They make sure to really investigate what's going on. Knowledgeable staff and clean environment. read more

Very responsive and helpful! Made me feel "heard" and well taken of. I recommend Advanced Gastronoenterology

Dr Simoni is a brilliant and caring Doctor. Under his care I have gotten healthy. His staff is a reflection of him as they are efficient and caring. I am so thankful to have found them and have sent my family to them which is the highest compliment I can give. Dorothy R read more

Great service! Very clean facility always on time love the appointment reminders by text great experience! Excellent staff and doctor.

I was referred to Dr. Simoni by my gastroenterologist b/c I have issues Dr.Simoni addresses. I have been to his office twice and have had an endoscopy. I am scheduling two more procedures with his office in coordination with Los Robles hospital. I have been very pleased with both Dr. Simoni the office staff. There is little wait time and the doctor takes times to explain everything thoroughly and to answer all my questions. I am looking forward to his help in resolving my issues. I have not encountered any insurance problems at this point. read more

I have been going to Dr. Simoni for years. He is the best. He is kind and cares about his patients. I have had numerous stomach issues and he is allways right on target. He shiws concern and takes the extra time to be sure. His office is efficient, friendly and are terrific about giving you all the necessary paperwork. I would highly recommend Dr. Simoni to anyone. read more

Dr Simoni now you are calling me abusive to you and your staff!! As a prior patient I find you calling me abusive is insulting!! Your medical services are not up to PAR!! You literally called me abusive publicly!! I will sue you, I have never been abusive to you or anyone in your staff!! Dr. Simoni you keep getting yourself in more hot water!! I am looking into suing you personally now!! I am in total shock that the doctor would say I was abusive! If you look at the previous review it sounds like he is saying the same thing about a prior patient being abusive and rude!! Everyone, if you go to filter and choose low rating reviews there are so many more serious bad reviews from many many prior patients of the Dr SIMONI!! Everyone their kinda hidden but I came across 8 reviews of Dr Simoni it says not recommend but please read this Doctor has so many complaints regarding his medical care of patients! And he retaliated by saying I abused him and his office! But he has accused so many many patients of abuse and being rude when that has never ever happened!! Wow warning everyone do not have Dr Simoni care for you he should not be allowed to care for anyone he is actually also a Gastro at Los Robles Hospital you don't want him in an emergency either for gastro issues!!!! Their are now 21 COMPLAINTS about Dr Simoni and his rude staff!! I am surprised I got a call from an employee of Dr. SIMONI, she was very apologetic about what people have gone through in the office! She stated their is no patient that she knows of that has been rude or abusive!! She stated that Dr. Simoni and Martha Simoni are not honest employers!! She also says it is so stressful for her in the office because they are constantly making up outrageous lies about patients!! And patients get upset because they lie to patients! She said her conscious working in that environment is so unprofessional and that she had to say something!! Thanks to honest people in the world!! She did say if I needed her to give a deposition she would be fine with going through any questioning!! It keeps getting more interesting this Dr SIMONI negligent care for his patients! I am determined to share all my experiences at Dr Simoni office!! A lot of unnecessary medical testing not needed!! read more