What can't stomach acid dissolve?

Stomach acid, also known as hydrochloric acid, is a strong acid that can dissolve many materials. However, it cannot dissolve certain substances that have a protective barrier or are resistant to acidic environments. For example, stomach acid cannot easily dissolve food particles, mucus, or the stomach lining itself due to their protective properties. Additionally, certain medications and supplements, such as enteric-coated pills, are designed to resist stomach acid to ensure they reach the intestines intact.