Penicillin, together with other antibiotics, has decreased the incidence and severity of many infectious diseases, such as pneumonia, tuberculosis and diphtheria, as well as treated ear, nose and throat infections, respiratory and urinary tract infections, prostate infections, and certain sexually transmitted diseases.

In addition to the ability to treat infectious diseases, the ability of antibiotics to control infection has made cardiac surgery, organ transplants, and treatment of severe burns now possible.

Although most penicillins are safe for the majority of people, some people may experience side effects or allergic reactions. The most serious of these is anaphylaxis, a severe allergic reaction that can cause skin rash, hives, itching, difficulty breathing, shock, and unconsciousness.

An early sign of anaphylaxis is a feeling of warmth and flushing.

If any of these occurs, the medicine should be stopped and emergency help sought immediately.

In some cases, these symptoms can progress to death. Also, if you notice blood in your urine, have large amounts of light-colored urine, or experience swelling of the face or ankles, difficulty breathing, or unusual tiredness or weakness, consult your doctor immediately.

Certain penicillins--amoxicillin and clavulanate, azlocillin, mezlocillin, oxacillin, or piperacillin--may occasionally cause dark or amber urine, pale stools, stomach pain, or yellow eyes or skin.