Heated, humidified air for the common cold

The common cold is the most common infection in humans. Considered trivial, it does not cause complications but leads to significant work absenteeism due to discomfort caused by the symptoms.The common cold is diagnosed according to the symptoms and treatments are mainly symptomatic. New information, especially regarding the effects of cytokines in human beings, now helps to explain some of the symptoms of colds and influenza, such as fever, loss of appetite, malaise, chilliness, headache, and muscle aches and pains. Many of these signs and symptoms are common and are attributed to congestion arising from swelling of the membranes and thickened mucus inside the nose.

The common cold has been treated for decades with inhaled steam in the hope the mucus drain away more easily. Also there is laboratory evidence that the cold virus may be sensitive to heat. No large-scale clinical trials have been undertaken to test the clinical efficacy of this therapy. However, steam inhalation continues to be used, as it provides subjective relief of common cold symptoms. This review reports findings from six trials conducted on 387 participants; 215 participants had a naturally acquired common cold and 172 healthy participants were inoculated with the common cold virus. We combined data from studies reporting the same outcomes. Studies conducted in Europe showed a positive effect whereas those from North America showed no benefit. Reported adverse effects included local discomfort, running of make-up and, in one study, increased nasal resistance. This review found that in some studies inhaling steam helped symptoms; in others it did not. The conclusion is that there is not enough evidence to support steam inhalation for the common cold. None of the studies included children.

Authors' conclusions: 

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.

Read the full abstract...

Heated, humidified air has long been used by sufferers of the common cold. The theoretical basis is that steam may help congested mucus drain better and heat may destroy the cold virus as it does in vitro.


To assess the effects of inhaling heated water vapour (steam) in the treatment of the common cold by comparing symptoms, viral shedding and nasal resistance.

Search strategy: 

In this updated review we searched CENTRAL 2013, Issue 2, MEDLINE (1966 to February week 4, 2013), EMBASE (1990 to March 2013) and Current Contents (1994 to March 2013).

Selection criteria: 

Randomised controlled trials (RCTs) using heated water vapour in participants with the common cold or participants with experimentally induced common cold.

Data collection and analysis: 

The two review authors independently reviewed all retrieved articles and excluded any articles, editorials and abstracts with inadequate outcome descriptions. The studies we included were subjected to a methodological assessment.

Main results: 

We included six trials (394 trial participants). Three trials in which patient data could be pooled found benefits of steam for symptom relief for the common cold (odds ratio (OR) 0.31; 95% confidence interval (CI) 0.16 to 0.60). However, results on symptom indices were equivocal. No studies demonstrated an exacerbation of clinical symptom scores. One study conducted in the USA demonstrated worsened nasal resistance, while an earlier Israeli study showed improvement. One study examined viral shedding and antibody titres in nasal washings; there was no change in either between treatment and placebo groups. Minor side effects (including discomfort or irritation of the nose) were reported in some studies.