A knowledge of cross-reactions between different allergens can facilitate the diagnosis of allergy. IgE cross-reactivity has been identified between house dust mite and snails. While most patients have mild symptoms, asthma and/or anaphylaxis may occur with these and other cross-reacting foods. It may be worthwhile to include measurement of IgE to some edible invertebrate animals in asthmatics, e.g. in mite allergic asthmatic patients who eat snails.