Symptoms of cow's milk allergy are non-specific; as a result, suspected cow's milk allergy is far more common than proven allergy to cow's milk. Cow's milk allergy in infants is therefore most probably a fairly uncommon clinical picture; cow's milk allergy is estimated to occur in less than one per cent of infants. The only valuable additional diagnostic tool is food challenge, preferably double blind. Therapy consists of a formula free of cow's milk (preferably containing extensively hydrolysed whey protein) from the moment the mother ceases nursing her child until the age of 6-12 months. Solids can be introduced in the usual fashion; there is no scientific basis for introducing them in a step by step fashion. Prevention of cow's milk allergy by using hypoallergenic formula (partially hydrolysed cow milk protein) in the first year of life has been shown to be unsuccessful, and can no longer be recommended. In the future, oral immunotherapy may be a promising new treatment for cow's milk allergy.