A family history of allergy and asthma identifies children at high risk of allergic disease. Dietary restrictions in pregnancy are not recommended. Avoiding inhalant allergens during pregnancy has not been shown to reduce allergic disease, and is not recommended. Breastfeeding should be recommended because of other beneficial effects, but if breast feeding is not possible, a hydrolysed formula is recommended (rather than conventional cow's milk formulas) in high-risk infants only. Maternal dietary restrictions during breastfeeding are not recommended. Soy formulas and other formulas (eg, goat's milk) are not recommended for reducing food allergy risk. Complementary foods (including normal cow's milk formulas) should be delayed until a child is aged at least 4-6 months, but a preventive effect from this measure has only been demonstrated in high-risk infants. There is no evidence that an elimination diet after age 4-6 months has a protective effect, although this needs additional investigation. Further research is needed to determine the relationship between house dust mite exposure at an early age and the development of sensitisation and disease; no recommendation can yet be made about avoidance measures for preventing allergic disease. No recommendations can be made about exposure to pets in early life and the development of allergic disease. If a family already has pets it is not necessary to remove them, unless the child develops evidence of pet allergy (as assessed by an allergy specialist). Women should be advised not to smoke while pregnant, and parents should be advised not to smoke. No recommendations can be made on the use of probiotic supplements (or other microbial agents) for preventing allergic disease at this time. Immunotherapy may be considered as a treatment option for children with allergic rhinitis, and may prevent the subsequent development of asthma.