The question of the possible role of food additives, and specifically food colours, in elevating hyperactive behaviour in children has been long debated. There is now replicated evidence that the removal of food colours from the diet can make a small improvement in the behaviour of some children with ADHD. However, as yet the characteristics of those who benefit from this dietary change are unknown. Two studies from a research group at Southampton have extended this work to show that some children from the general population without ADHD show a similar benefit. The implications of these findings for those in CAMH services are discussed. They are considered alongside other forms of dietary treatment for ADHD such as the use of ‘few foods’ diet and omega-3 fatty acids.