Antibiotic treatment of acute upper respiratory tract infections (URI), especially nonspecific respiratory tract infections (common cold) and acute bronchitis, is inappropriate in almost all occasions because they are usually caused by nonbacterial infections. Purulent secretions from the nares or throat do not indicate bacterial infection or benefit from antibiotic treatment. Antibiotic treatment of adults with non-specific URI does not facilitate the resolution of illness or prevent complications. Acute pharyngitis and acute sinusitis sometimes have a bacterial cause, and antibiotic treatment is generally not justified unless otherwise indicated. Streptococcus pyogenes is the cause of acute pharyngitis only in 5~15% of adult patients. Therefore, antibiotics are recommended to patients who are highly likely to have streptococcal pharyngitis. Following strategies would be appropriate: 1) limit the antibiotic trea-tment to patients with three or four criteria, that is, fever, tonsillar exudates, no cough, and tender anterior cervical lymphadenopathy; or 2) test patients with two or three criteria by using a rapid antigen test, and limit antibiotic treatment to patients with positive test results or those with four criteria. Most patients with viral URI nearly recover within 7~10 days, and acute bacterial rhinosinusitis is not common in patients whose symptoms last for less than 7 days. Patients without purulent nasal discharge, maxillary facial or tooth pain or tenderness, or both are unlikely to have bacterial rhinosinusitis, regardless of the duration of illness. Antibiotic treatment is appropriate for patients with specific symptoms of 10 days or longer. Lastly, the choice of antibiotics should be based on the epidemiologic data on susceptibility of major pathogens.