In pictures: Penicillin: The first 'wonder drug'

As a family of drugs, antibiotics are used against bacterial infections.

Penicillin is specifically used to treat tonsillitis, pharyngitis, bronchitis and pneumonia.

It is also used against the sexually transmitted diseases syphilis and gonorrhoea.

The drug is known as a broad- spectrum antibiotic because it kills a wide range of bacteria.

Photo credit: Cordelia Molloy/Science Photo Library