Paracetamol is being linked to the development of asthma in children.

The proportion of UK children with asthma trebled between the 1960s and the mid-1990s and there are now 5.2 million Britons receiving treatment for the condition.

Researchers found taking paracetamol once a month more than tripled the chances of asthma attacks in six and seven-year-olds.

The drug has also been associated with an increased risk of hayfever and eczema.

Scientists believe paracetamol may cause changes in the body that leave a child more vulnerable to inflammation and allergies.

Although the study authors cannot be sure that taking paracetamol is causing the disease, rather than merely being associated with it, there are good reasons to believe this is the case.

The research highlights a dose-dependent response with more exposure to the drug resulting in more asthma attacks.

Exposure also tended to precede the response, pointing to a cause-and-effect relationship.

The study, part of a worldwide investigation called the International Study of Asthma and Allergies in Childhood (ISAAC), spanned 73 centres in 31 countries.

It found that giving children paracetamol in the first year of life increased the risk of later asthma symptoms in six and seven-year-olds by 46 per cent.

Among the older children, "medium use" of paracetamol - taking the medicine at least once a year - increased the risk of asthma symptoms by 61 per cent compared with no use.

Taking paracetamol at least once a month - classified as "high use" - increased the symptoms risk 3.23 times.

Paracetamol was also associated with a 22 per cent - 38 per cent higher risk of severe symptoms resulting in multiple wheezing attacks, disturbed sleep, or being too breathless to speak.

Using the drug in the first year of life increased the risk of hayfever and eczema at the age of six and seven by 48 per cent and 35 per cent respectively.

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