The antibiotic tetracycline is being taken for seven days or less by pneumonia and other infections involving the respiratory tract and other infections of the skin and urinary systems that are bacterial in nature. It is an antibiotic that combines with the 30S ribosomal subunit that hinder in translation by supressing the growth of bacteria. By this action, the ability of the ribosomes to integrate proteins for the growth and endurance of the bacteria will be damage and eventually kill the bacteria.