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Dr. John Fahy is a pulmonologist who has a special interest in treating patients with asthma and serves as director of UCSF’s severe asthma clinic. He also cares for critically ill patients in the intensive care units.

Fahey directs the UCSF Airway Clinical Research Center. His research receives funding from the National Institutes of Health and various foundations, as well as contracts from biotechnology and pharmaceutical companies. The center studies the underlying disease mechanisms of asthma, cystic fibrosis and other airway diseases.

Fahy earned his medical degree at University College Dublin After internal medicine training in Dublin, he completed fellowship training in pulmonary and critical care medicine at UCSF. He joined the faculty in 1993.

He is the Michael S. Stulbarg Endowed Chair in Pulmonary Medicine.

  • Education

    University College, Dublin Ireland, 1985

  • Residencies

    University College Dublin, Internal Medicine, 1989

  • Fellowships

    UCSF, Pulmonary Medicine, 1992

  • Board Certifications

    Internal Medicine, American Board of Internal Medicine

  • Academic Title


Where I see patients (2)

    My reviews


    Overall Experience
    54 Ratings
    About our process
    Aug 04, 2023
    Very nice manner of listening. I look forward to working with Dr. Fahy in managing my lung issues!
    Jul 07, 2023
    Dr. Fahy provides a level of care about my health that is unusual and very much appreciated.
    Jun 16, 2023
    Dr. Fahy is a very compassionate empathetic doctor and ai am lucky to be under his care.
    Jun 12, 2023
    Dr. Fahy was outstanding and recommended many helpful ideas.
    Jun 11, 2023
    Dr. Fahy squeezed me in due to the severity of my infection and I am so grateful to him.
    Mar 25, 2023
    Dr Fahy listened and seemed to care.
    Feb 03, 2023
    Couldn't answer follow up care plan question because diagnostic test results weren't finalized by the time of my appttwo weeks later!
    Dec 30, 2022
    Dr Fahy is an excellent and thoughtful physician
    Dec 25, 2022
    Dr Fahy is the very best medicine can offer! He is a phenomenal doctor and I would. Come from around the world to see him here!
    Nov 18, 2022
    I have met with this provider 4 times since 2017. I don't fit in a particular diagnosis so he doesn't quit know what to do with me. It's frustrating for me but also I think for him.
    Nov 09, 2022
    Oct 14, 2022
    Dr Fahy is very knowledgeable. He is also very concerned about my health and willing to try new medication to improve my condition.
    Sep 09, 2022
    Dr Fahy is the best
    Jul 29, 2022
    Very good doctor
    Feb 25, 2022
    This was a very interactive visit.
    Decorative Caduceus

    The Effects of Positive Airway Pressure on the Mucolytic Effects of NAC (TEAM)

    The primary outcome is the % change in mucus plug score from 1 week before treatment to 1 week post treatment.


    Decorative Caduceus

    Impact of Metabolic Dysfunction and Mucus Plugging on Asthma Physiology

    We will compare change in EELV during the CPET (Cardiopulmonary Exercise Test) between the obese asthma patients with MD or without MD and between the patients with severe asthma with mucus plugs or without mucus plugs.


    Decorative Caduceus

    Tissue Immune Interaction in Nasal Polyposis

    This study enrolls chronic rhinosinusitis patients with and without nasal polyps. Investigators aim to compare the percentage of ILC2 and tuft cells present in nasal tissue and secretions between those who present with nasal polyp...


    Decorative Caduceus

    Lung Function Outcomes Following Removal of Airway Mucus Plugs in Patients With Asthma (FOCUS)

    We will assess change from baseline FEV1 one week after and six months after removal of mucus plugs by bronchoscopy.


    Decorative Caduceus

    PrecISE (Precision Interventions for Severe and/or Exacerbation-Prone Asthma) Network Study

    Assessed prior to bronchodilator administration. Efficacy analyses will compare the end-of-period outcome values between test treatment and placebo.


    Decorative Caduceus

    Blood Lymphocytes in Asthmatics Treated With Therapeutic Proteins

    The investigators will compare lymphocyte counts in healthy controls to asthmatics on and off therapeutic proteins.


    Decorative Caduceus

    CF And Effects of Drugs Mixed Ex Vivo With Sputum for Mucolytic Treatment


    Decorative Caduceus

    The Effect of NAC on Lung Function and CT Mucus Score

    The primary outcome is the % change in FEV1 from the start to the end of each two-week treatment period (either placebo or 20% NAC).