Almost all colds are caused by a virus, for which antibiotics are not an effective treatment.

1,439 patients with 2,171 outpatient and emergency department visits for the common cold (acute nasopharyngitis) from a random sample of 50,000 patients with at least one claim for care by a physician, dentist, or optometrist.

Kentucky Medicaid claims data, July 1, 1993, to June 30, 1994.

In 60% of encounters for the common cold, patients filled prescriptions for antibiotics.

Mainous et al., 1996

Same as above.

Patients ≥ 18 years old with a diagnosis of the common cold, exclusive of adults with underlying lung disease, from a nationally representative sample of 1,529 physicians representing 28,787 adult patient ambulatory care visits.

National Ambulatory Medical Care Survey (NAMCS), 1992.

51% of patients diagnosed with a cold were treated with antibiotics.

Gonzales et al., 1997