Antibacterial activities of several ‘non-antibiotic drugs’ used in treatment of a variety of non-infectious human diseases have been observed. Such an effect has been noticed for barbiturates, beta-adrenergic receptor antagonists, diuretic drugs, H1 antihistamines, mucolytic agents, nonsteroid anti-inflammatory drugs, proton pump inhibitors and psychotherapeutic drugs. A synergic or antagonistic effect with antibiotics of several of these drugs have also been noticed. In this overview the knowledge in the field is summarized, omitting hormones, drugs with local effects and those with low therapeutic indexes. Therapeutic implications and future considerations are discussed.