The beginning of antibiotic era is traditionally ascribed to Fleming's discovery of penicillin in 1928. From the modern view, however, the term "antibiotic" includes all antibacterial drugs for oral or parenteral administration, regardless of their origin (microbial products or chemical compounds). Thus, sulphonamides belong to antibiotics, with the beginning of antibiotic era dating back to the year 1910 when Paul Ehrlich and Sahachiro Hata demonstrated the therapeutic potential of arsphenamine (Salvarsan) against syphilis. The discovery of penicillin was preceded by studies from several countries that documented antagonism between various microorganisms. Some of them resulted in the introduction of new antibacterial drugs. Nevertheless, these drugs could be used only for local treatment of superficial infections. Alexander Fleming did discover penicillin but the medical use of this substance was the result of an effort of Howard Florey's Oxford team. The enthusiasm for penicillin led to several recommendations that were incorrectly ascribed to all antibiotics. Examples of such misinterpretations are provided in the article.