SER-109 is an investigational oral medication designed to treat recurrent Clostridioides difficile infection (CDI). It is composed of a mixture of live bacteria, specifically designed to restore the balance of gut microbiota disrupted by antibiotic treatments. The treatment aims to reduce the recurrence of CDI by re-establishing a healthy gut environment. Clinical trials have shown promising results, indicating that SER-109 may significantly lower the risk of future infections compared to standard therapies.