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Dr. B. Mark Zhao is a colorectal surgeon who cares for patients with conditions of the colon, rectum and anus. His expertise encompasses inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis; colon, rectal and anal cancers; diverticulitis (infection or inflammation of small pouches in the intestines); and pelvic floor disorders, including rectal prolapse, fecal incontinence (problems with bowel control) and constipation. He specializes in using minimally invasive surgical techniques to treat many of these conditions, including transanal endoscopic microsurgery (a procedure using special instruments to remove rectal tumors without surgical incisions). He also performs colonoscopies and endoscopies to screen for or diagnose conditions of the colon and rectum.

Zhao conducts research on colorectal surgical outcomes, with the goal of making these procedures safer and more effective. He has a particular interest in using biomedical informatics (health-related datasets) to improve patient care.

Zhao earned his medical degree from the University of Iowa Carver College of Medicine. He completed a residency in general surgery at the University of California, San Diego, where he also earned a master of advanced study degree in clinical research and completed a fellowship in clinical informatics. He completed a fellowship in colon and rectal surgery at Washington University in St. Louis, training at Barnes-Jewish Hospital.

  • Board Certifications

    American Board of Colon and Rectal Surgery, Colon and Rectal Surgery

    American Board of Preventive Medicine/Toxicology, Clinical Informatics

    American Board of Surgery, Surgery

  • Fellowships

    Washington University School of Medicine

  • Residencies

    University of California San Diego-General Surgery, General Surgery

    University of California San Diego-General Surgery, General Surgery

  • Degree

    MD, University of Iowa Carver College of Medicine

As a colorectal surgeon, I am devoted to providing compassion, empathy and unwavering support to all my patients through challenging times.

Where I see patients (1)

    My reviews

    4.9

    Overall Experience
    122 Ratings
    About our process
    Jun 28, 2025
    Dr Zhao is one of the most patient incredibly intelligent doctors I've ever met. Really listens to his patient and takes time to explain things.
    Jun 12, 2025
    Dr and NP are wonderful, and I feel so taken care of
    May 10, 2025
    He's great!
    May 08, 2025
    Extremely caring
    May 03, 2025
    Extraordinair
    Apr 25, 2025
    Excellent care by Dr. Zhao.
    Apr 10, 2025
    Everything is at the highest level. Thank you very much to the doctors
    Mar 24, 2025
    Dr. Zhao wrote down everything we needed to do for future care and what the next steps were. It would also be helpful if that same info was also in our summary visit within the MyChart app.
    Mar 15, 2025
    All good
    Feb 08, 2025
    Very nice Doctor
    Feb 08, 2025
    Caring & compassionate provider !
    Feb 06, 2025
    Stellar experience. Doctor treated me like an equal, was warm and friendly, and provided a good deal of information.
    Feb 02, 2025
    Dr Zhao gave found advice on a very complex medical problem.
    Dec 15, 2024
    Dr. Zhao was excellent to work with. He had obviously prepared thoroughly for my visit and inspired my complete confidence in his skills as a physician and surgeon.
    Dec 06, 2024
    Dr.Zhao & Diana Rago are true professionals. They treat you with respect and make you feel like you are important to them .
    Aug 03, 2024
    Dr.Zhao makes you feel comfortable and is very personable.
    Jul 11, 2024
    5 star experience during a difficult time makes a world of difference. It's so nice to have a doctor that shows emotion and empathy
    Jun 18, 2024
    Everything was excellent
    Jun 16, 2024
    Professional, knowledgeable, kind-highly recommend
    Jun 05, 2024
    Care provider was excellent.
    Apr 27, 2024
    Kind. Supportive. Clearly very knowledgeable
    Apr 27, 2024
    Excellent Dr Zhao and staff
    Apr 20, 2024
    Superb!
    Mar 28, 2024
    Mark Zhao was excellent. Caring, clear, and with a sense of humor, which given his area of practice, is useful.
    Mar 09, 2024
    Dr. Zhou is awesome!
    Mar 08, 2024
    All are very good

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