This preliminary study evaluated the effectiveness of enteric-coated erythromycin in the treatment of adults with nonstreptococcal pharyngitis. Twenty-six patients, aged 12 or older, with nonstreptococcal pharyngitis were randomly assigned in a double-blind fashion to receive either enteric-coated erythromycin or placebo for 10 days. Each day the patients rated the soreness of their throats and how sick they felt. The use of erythromycin appeared to decrease the median number of days for the feeling of sickness to improve (two days versus four days, P less than .01) as well as to decrease the median number of days for the feeling of sickness to resolve (three-and-a-half days versus five days, P less than .05). This apparent improvement in sickness occurred even though there was no significant decrease in the soreness of the throat in patients treated with erythromycin compared to those patients treated with placebo. Treatment with enteric-coated erythromycin appeared to shorten the time until improvement in this group of adults with nonstreptococcal pharyngitis.