The pathogenesis of symptoms of the common cold and their optimal treatment are incompletely understood. To evaluate the role of an oral alpha agonist alone and in combination with a nonsteroidal anti-inflammatory drug in the treatment of experimental rhinovirus colds, 58 subjects were randomized to receive pseudoephedrine 60 mg alone, pseudoephedrine 60 mg plus ibuprofen 200 mg, or placebo, four times daily for 4 1/2 days beginning 30 hours after intranasal rhinovirus inoculation under double-blind conditions. The frequencies of infection, colds occurrence, and viral shedding did not differ significantly between the groups. Total symptom scores were reduced by 59% by pseudoephedrine plus ibuprofen (p less than 0.05) and 48% by pseudoephedrine alone compared with placebo. Nasal symptom scores tended to be lower in recipients of pseudoephedrine plus ibuprofen compared with pseudoephedrine alone (p = 0.09), but other parameters showed no significant treatment differences between the groups. Rhinorrhea, as determined by nasal secretion weights, was significantly reduced in both treatment groups compared to placebo. Nasal patency measurements tended to show the greatest improvement in recipients of pseudoephedrine plus ibuprofen. Therapy was clinically well tolerated. The results suggest that an oral alpha agonist is effective in modifying certain manifestations of experimental rhinovirus infection and that the addition of a nonsteroidal anti-inflammatory drug may provide additional benefit in nasal symptoms and patency. Studies involving large numbers of patients with natural colds are needed to determine the clinical significance of these findings.