Contact dermatitis is a reaction that happens after your skin comes in contact with certain substances. Skin irritants cause most contact dermatitis reactions. Other cases are caused by allergens, which set off an allergic response.

Acne affects teens and adults of all ages. It happens when oil secreted by sebaceous glands clogs the hair follicle. Bacteria infect the clogged follicle and cause pimples.

An inguinal hernia is when part of your intestine pushes through a weak spot in your lower belly (abdominal) wall. This area is called the groin. The hernia creates a lump in your groin. Over time, the hernia may get bigger.

GERD (gastroesophageal reflux disease) is a digestive disorder. It is caused when gastric acid from your stomach flows back up into your esophagus.

Smoking tops the list of risk factors for heart disease. Learn more about how smoking affects your heart--as well as helpful tips to quit smoking.

Detailed information on how the digestive system works, including a full-color, labeled illustration of the digestive system.

A pacemaker is a small device implanted under the skin that sends electrical signals to start or regulate a slow heartbeat.

The mitral valve sits between the left atrium and left ventricle. It's job is to keep blood flowing in the right direction. Mitral valve prolapse is the bulging of the valve causing blood to leak backwards.

Heart murmurs may be caused by a number of factors or diseases, including defective heart valves, fever, and pregnancy. Read on to learn more about this condition.

With advances in technology, pacemakers and ICDs generally last several years and, in most cases, allow a person to lead a normal life.