Recent reports of the benefits of helium/oxygen gas mixtures (heliox) use for the relief of dyspnoea and exercise limitation have stimulated interest in the use of heliox in the palliation of dyspnoea especially in chronic obstructive pulmonary disease patients. With better understanding of the mechanistic causes of dyspnoea in these patients theoretical benefits of heliox have been suggested. This report considers the evidence to support this role and reviews the current position on heliox administration and use as a carrier gas for nebulization therapies.Heliox can effectively improve exercise limitations, decrease the work of breathing and reduce dyspnoea in lung cancer and chronic obstructive pulmonary disease patients; in the latter it works by reducing dynamic hyperinflation. The evidence comes from short-term assessments of single exercise tests and additional benefits are seen when used in conjunction with other current therapies such as supplemental oxygen and nebulization. Dedicated devices with better comprehensive guidelines for administration have been developed to alleviate some of the reluctance of use.Heliox use could prove beneficial either administered alone or as an addition to current therapies for the palliation of dyspnoea and give significant improvement in outcomes of rehabilitation programmes. There is still an urgent need to identify which patients are the best candidates for heliox use and translate the significant short-term benefits into long-term improvements in functioning and quality of life.