Ozone has been used in medicine for over a century, beginning with applications such as disinfecting medical equipment and supporting wound care. Over time, its use expanded in parts of Europe and other regions as a tool in integrative and alternative medicine. Today, ozone therapy is still being studied for its potential roles in immune modulation, circulation, and oxidative balance. Regulations and accepted uses vary by country, and in the United States it is generally considered a complementary therapy. Anyone interested in ozone therapy should review the risks, benefits, and current evidence with their healthcare provider before starting treatment.