Anti-asthma medication alone cannot be considered a complete treatment for asthma. Drugs have not made an impact on asthma mortality, yet may cause significant side-effects. Minimising exposure to environmental allergens decreases the severity of asthma attacks and therefore decreases the amount of medication required and the likelihood of side-effects. The identification, avoidance and elimination of allergens should therefore play a central role in the management of any child with asthma. Studies in Asia and Europe have shown a positive correlation between affluence, indoor pollution, and the prevalence of asthma. There is evidence to suggest a relationship between exposure to allergens before the age of 1 year and later allergen sensitivity, through the promotion of TH2 cell dominance. Of particular importance are maternal smoking, house dust mites and cockroach allergens. The methods for reducing house dust mite exposure are many and varied and include acaricides, encasement of bedding material, vacuuming, exposure to sunlight, dehumidification, hot washing and air filtration.