A new survey has found that one in three Britons does not know the difference between common painkillers, and just take whatever they can find when in pain.
The study, commissioned by Panadol, found a widespread awareness that some medicines were unsuitable for certain conditions, but a lack of understanding over which ones should be avoided.
Women, however, proved more sensible than men, with 39 per cent being careful over their medication, compared with only 27 per cent of men.
"There are issues with people not knowing what's in their medicine. If someone has asthma, for example, then taking aspirin or ibuprofen could make it worse," Hooman Ghalamkari, a pharmacist, told the BBC.
"There are safeguards in a pharmacy because as professionals we can advise people. But you can also buy these painkillers in supermarkets where are aren't the same safeguards in place," he added.
The research has been released at the start of Ask About Medicines Week, a yearly campaign to make people more aware of the drugs they take and the importance of carefully reading labels.
An explanatory leaflet – Ask About Pain Relief – will be available from GP surgeries shortly.