Questions are being raised over the effectiveness of cold and flu medicines.
Many cold and flu medicines are expensive and not likely to be more effective than regular painkillers and putting your feet up for a rest, a consumer advocacy group says.
"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.
The group looked at more than 50 cold and flu products to see which offer the most effective relief.
It reviewed research on typical ingredients in the remedies and found many had unconvincing scientific evidence to back up their claims.
Independent reviews into ingredients in cough medications -dextromethorphan and guaifenesin - have also not found good evidence of their effectiveness, Consumer NZ says.
"Despite the lack of evidence, these products can be expensive - with some costing up to $30."
Consumer NZ has raised its concerns with Medsafe, the Ministry of Health agency tasked with ensuring over-the-counter medication is safe and effective, Ms Chetwin says
"Like any product, cold and flu remedies should be true to label and do what they say they'll do," she says.
In its report, Consumer NZ found more convincing evidence medicine-cabinet staples - such as paracetamol, ibuprofen and aspirin - can help ease the aches and discomfort from cold or flu and that decongestant nasal sprays may help.
"There is no cure for the common cold. The best prescription for beating a winter bug is taking a few days' rest at home," it said.