One in 20 people also took painkillers straight after a heavy drinking session, wrongly believing it would prevent a hangover.
The pills are generally taken in secret, as one in six people admitted they would not tell a health professional how many they take.
Ignoring recommended dosages could lead to liver damage and prove fatal but one in 10 people questioned said they would take painkillers every day of the week, or for longer.
One in four people said they took them to cope with stress and more than one in 20 popped a pill because it "made them feel better".
Janice Perkins, of The Co-operative Pharmacy, said: "People should always read the patient information leaflet that comes with their medicine.
"Taking too much paracetamol is particularly dangerous because it can cause liver damage, which may not be obvious and an overdose of paracetamol can be fatal."
Around one in eight said they took paracetamol with a flu remedy already containing an analgesic while one in 20 mixed painkillers without knowing which active ingredients they contained.