The current version of ANSI/ASHRAE/ASHE Standard 170 (2013) precludes natural ventilation in all spaces in health care facilities. This task group suggests it should be allowed in most health care spaces, except for operating rooms, procedure suites, sterile core areas, interventional radiology or cardiology spaces, airborne isolation areas, and protective environments. Natural or mixed-mode ventilation designs may offer some benefits. Among the most likely are energy reduction and enhance occupant satisfaction. Less likely benefits may include enhance indoor air quality and a more beneficial microbiome. When considering natural ventilation in health care, designers must fully address the fundamental challenges of space appropriateness, climate appropriateness, acoustics, security, and outdoor air quality. Projects implementing natural ventilation should anticipate commissioning challenges. Many commissioning and air balance providers in the United States are not experience with natural ventilation system. Some U.S. designers or owners may be adverse to natural ventilation because of it newness, added costs, or perceived impacts on clinical outcomes.