Nearly a fifth of people claim to have taken prescription medicines incorrectly, highlighting the important role a live-in carer can play in helping with pills.
Researchers for Lloydspharmacy polled nearly 2,000 people and found that many people had misread labels, taken the wrong dose, or taken drugs at the wrong time.
Nearly 1.8 million people in the UK are estimated to have suffered an adverse reaction as a result of taking medicines wrongly.
Pharmacy director Andy Murdock commented: "We know that many patients choose not to complete their course of medication, but this study reveals a different type of problem - patients who, for whatever reason, take their medicines incorrectly."
Mr Murdock said that pharmacists encounter many patients who are confused by their medication.
"The biggest issues are among those who are taking more than one prescription medicine at a time, but the problem also seems to be more acute among older patients," he revealed.
Patients are advised to consider a medicines use review (MUR) if they have been taking a drug for a long time or take a number of different drugs.
This will ensure they are taking their medicines properly and that they are working.