Steam inhalation has not shown any consistent benefits in the treatment of the common cold, hence is not recommended in the routine treatment of common cold symptoms until more double-blind, randomised trials with a standardised treatment modality are conducted.
Effect of inhaling heated vapor on symptoms of the common cold.
To test the efficacy of steam inhalation in treating common cold symptoms.
                An in vitro study determined the temperature that inactivated rhinovirus: a temperature of 43 degrees C lasting at least 1 hour was needed. We then conducted a double-blind, placebo-controlled, randomized in vivo study.
                The virology laboratory and the outpatient department of the Cleveland (Ohio) Clinic Foundation.
                Sixty-eight Cleveland Clinic employee volunteers with symptoms of the common cold at the time of enrollment.
                A single 60-minute treatment was given to the volunteers. The steam treatment group (n = 32) received 40 L/min of heated saturated air that raised the intranasal temperature to 43 degrees C. The placebo group (n = 36) received 2 L/min of ambient air at 20 degrees C to 24 degrees C.
                Subjective symptom scores for nasal congestion, nasal drainage, and sneezing and objective measures of nasal resistance were studied during a 7-day follow-up observation period.
                There were no significant differences in daily symptom scores between the groups (P = .59 to .83). The only statistically significant differences between the groups were lower nasal resistances at baseline in the steam group (P = .04) and percent improvement in nasal resistance favoring the placebo group on day 7 (P = .01). However, these differences were of questionable clinical significance.
                We conclude that steam inhalation treatment had no beneficial effect on the cold symptoms of our volunteers.