Expensive over-the-counter cold and flu remedies are often no more effective than paracetamol, honey and putting your feet up for a few days, says Consumer NZ.

“People hit by a winter bug may want to save their money and stick with bed rest and a painkiller,” Consumer NZ chief executive Sue Chetwin says.

Consumer NZ looked at more than 50 cold and flu products, from decongestants and antihistamines through to cough drops, to see which offer the most effective relief.

It reviewed research on typical ingredients in cold and flu remedies and found many products had unconvincing scientific evidence to back up their claims.

Despite the lack of evidence, these products can be expensive — with some costing up to $30.

Ms Chetwin says independent systematic reviews of the ingredients found in common cough medications (dextromethorphan and guaifenesin) have not found good evidence of their effectiveness.

Much of the supporting research on the decongestant phenylephrine was also conducted more than 40 years ago and many of the studies had design flaws, she says.

“Consumers who buy a product that says it will clear their nose and ease their cough should be able to expect there’s consistent evidence to support the claim. But that’s not the case with many cold and flu products.”

Ms Chetwin says Consumer NZ has raised its concerns with Medsafe, the Ministry of Health agency tasked with ensuring over-the-counter medication is safe and effective.

“We have asked Medsafe to review the effectiveness and marketing of these ingredients. Like any product, cold and flu remedies should be true to label and do what they say they’ll do.”

In its report, Consumer NZ found more convincing evidence that medicine cabinet staples such as paracetamol, ibuprofen and aspirin can help ease the aches and discomfort from cold or flu. Studies also suggest decongestant nasal sprays may help ease that “bunged-up” feeling.

There is no cure for the common cold. The best prescription for beating a winter bug is taking a few days’ rest at home.

More information is available in our full report.