Antibiotics are medications used to treat infectious diseases that result from bacteria. Antibiotics include well-known medications such as penicillin (one of the earliest antibiotics) and erythromycin. They are often given to patients with certain types of valvular heart disease prior to surgical or dental procedures to help prevent infection in and around the heart muscle. 

In the past, antibiotics have been routinely recommended to prevent bacterial infections of the heart before dental procedures. In 2007, however, the American Heart Association issued revised guidelines for the use of preventive antibiotics before dental procedures. According to the new guidelines, most people who were taking antibiotics no longer need them. The only people who are currently advised to get preventive antibiotic treatment before common dental procedures are those at risk for bad outcomes due to infective endocarditis, or a bacterial infection of the innermost layer of heart tissue.

Antibiotics, however, are still crucial in the treatment of bacterial infections of the heart that may cause endocarditis, myocarditis, pericarditis, all of which are inflammation of different layers of the heart and valves. If a patient suffers from one of these conditions, and the condition is caused by bacterial infection, they will be prescribed powerful antibiotics.

Antibiotics, which are commonly taken either orally or intravenously, only attack bacterial infection. They have no effect on viruses,fungal infections or parasites. Antibiotics are created completely or partially from certain microorganisms. In some cases, the antibiotics kill the bacteria directly. In other cases, they prevent the bacteria from reproducing, allowing the immune system to destroy any remaining bacteria.

Different antibiotics or combination of drugs may be used to treat various conditions. It is important for individuals to take all of their prescribed antibiotics, even if their symptoms improve after only a few days. Otherwise, the bacteria are only weakened instead of totally destroyed. The weakened bacteria can change (mutate) and re-attack the patient. Whenever the bacteria change form, the patient is at increased risk of being infected by a strain of bacteria that is resistant to the antibiotic they have been given. This antibiotic resistance has become a worldwide problem with the emergence of bacteria strains that are resistant to all but the strongest antibiotics.

In addition to taking all of one's prescribed antibiotics, the general public is urged to avoid “antibacterial” soaps and similar products, which have been shown to increase bacterial resistance. In hospitals, however, antibacterial gel has been shown to reduce in-hospital acquired infections, a major source of illness.

Although antibiotics can treat many diseases, they can occasionally cause side effects, including gastrointestinal problems. In addition, antibiotics can interact with other drugs and medications. They can reduce the effectiveness of certain medications (e.g. birth control pills, antacids) and increase the effect of others (e.g., anticoagulants, bronchodilators). Patients should tell their physician about all prescription medications, over-the-counter drugs, herbal remedies and vitamin supplements that they are taking when antibiotics are prescribed.