SummaryLaboratory and field studies on the use of liquid nitrogen as an acaricide, combined with vacuum cleaning, demonstrated this inert freezing agent to be extremely efficient in reducing the number of live mites in mattresses when compared to vacuum cleaning only. Preliminary observations suggest this treatment does no physical damage to mattresses. Any strategy in the control of house dust mites should incorporate procedures both for the reduction of the mite population and the removal of the allergen pool of faecal pellets and dead mites.