Antibiotics are prescription medications taken to treat bacterial infections. Sometimes, doctors and dentists recommend taking antibiotics as a preventative measure. This practice is called antibiotic prophylaxis. There are millions of bacteria in your mouth that can enter the blood stream during dental exams and procedures. For most people, these bacteria do not cause a problem and no antibiotics are needed. However, patients who have heart conditions or heart defects are recommended to have antibiotics administered before any dental procedure. Always tell your dentist about any changes to your health and all medications you are taking. With this information, your dentist will be able to make the right decision for you about antibiotic prophylaxis.