Prescriptions charges in England should be reviewed as thousands of people are not collecting medicines because of cost, Citizens Advice has said.
Prescription charges raise £430m a year in England
It follows a poll of 880 people which found 2% were put off by the price - a total of 800,000 if the proportion were repeated across the whole of England.
Wales has already introduced free prescriptions while Scotland has promised to follow suit.
But ministers in England are still refusing to drop the £6.85 charge.
Citizens Advice said the poll, carried out for it by Mori, showed there was an urgent need for the government to review prescription charging.
The organisation's chief executive David Harker said: "It is unacceptable that people are still failing to collect prescriptions because they can't afford it.
"Evidence from our bureaux shows that prescription charges can seriously damage your health and the impact is felt most severely by people on low incomes and with long-term health problems.
"We are urging the government to review the issue of prescription charging as a matter of urgency to address the issue of prescription poverty in England.
"The progress in Wales and Scotland shows there is a strong case for abolishing prescription charges in England altogether."
HAVE YOUR SAY
Prescription charges are, in effect, a stealth tax on the sick
James Uscroft, Hanley
The government ruled out any move towards free prescriptions in England.
Ministers are planning to launch a consultation in the near future, but this will only be looking at "cost-neutral" ways of tweaking the system.
At the moment, people over 60, children and those on low incomes are exempt from payment.
People needing regular prescriptions are also entitled to apply for a pre-payment scheme which means they can get unlimited prescriptions for under £2 a week.
The government said the system meant that just one in 10 prescription items were charged at the full price.
A Department of Health spokeswoman added: "Prescription charges provide a valuable contribution to the NHS in England, estimated to be £430m for 2006-7.
"Abolishing them would significantly reduce the money available to deliver other health priorities."