Until the early 20^th century, the search for satisfactory antibacterial therapy was unsuccessful. Penicillin was the first natural antibiotic discovered by Alexander Fleming in 1929. However, a widespread use of antibiotics to treat infections did not occur until 1944, and since then they have become a cornerstone of modern medical treatment. Looking back, the use of antibiotics has been saving lives for more than half a century. In Europe the mortality rate related to infections declined from 30-35 percent in 1910 to 1-4 percent in 1990.