Best-selling Sanatogen vitamin pills are dyed with harmful additives

Britain's best-selling vitamin pill is dyed with artificial colours which can cause rashes and hyperactive behaviour in children.

Two colours – sunset yellow and quinoline yellow – criticised in an official study which led to their censure by the Food Standards Agency (FSA) last week – are found in Sanatogen Gold, the country's leading multivitamin brand.

Sanatogen's Kids A To Z Strawberry Flavour vitamins have another suspect additive: the red colouring Ponceau 4R.

Many customers may have been unaware of the presence of the additives because they are listed by name without their E-numbers in small print in the middle of a long list of ingredients on vitamin pill containers. On its website, Sanatogen acknowledges that the artificial colours are ingredients in its products but claims they are "non-allergenic".

However, EU guidelines state that, if used in medicines, all three colours would have to carry the warning: "May cause allergies". Ponceau 4R and quinoline yellow can cause skin problems including hives and eczema in a small number of people, and are banned in the US.

Last week, the FSA called for a European Union ban on six additives, including the three currently used by Sanatogen, because they made children more hyperactive in a £750,000 study carried out by Southampton University.

The regulator has called for British manufacturers to remove the additives from hundreds of fizzy drinks, cakes, sweets and chocolates by 2009.

Sanatogen, owned by the healthcare giant Bayer, which has vitamin sales of £40m, made no comment.