New guidance suggests that millions more people in England and Wales should be prescribed cholesterol-lowering statins in a bid to reduce the number of heart attacks and strokes.
Currently, people with a 20 percent risk of developing cardiovascular disease within 10 years are offered statins.
But the National Institute for Health and Care Excellence (NICE) said in draft NHS guidance that they should be offered to those with a ten percent risk.
Statins are currently taken by some seven million people in Britain, according to NICE.
They help lower rates of low-density lipoprotein (LDL) cholesterol -- known as "bad cholesterol" -- in the blood.
Professor Colin Baigent of Oxford University has calculated that lowering the threshold to ten percent would lead to some five million more people taking the drugs.
The NHS estimates that statins save around 7,000 lives a year in Britain.
Cardiovascular diseases are the leading cause of death in England and Wales, accounting for 180,000, or a third, of all deaths in 2010.
Professor Mark Baker, director of NICE's centre for clinical practice, said: "Smoking, high blood pressure and raised cholesterol levels are big causes of cardiovascular disease, especially in people with more than one of the factors.
"But the risk is measurable and we can substantially reduce someone's chance of a heart attack, angina, stroke and the other symptoms of cardiovascular disease by tackling the risk factors.
"People should be encouraged to address any lifestyle factors such as smoking, drinking too much or eating unhealthily.
"We also recommend that statins are now offered to many more people - the effectiveness of these medicines is now well proven and their cost has fallen."
The NHS says most people taking statins will not experience side effects but that these can include insomnia, headaches and, in rare cases, memory loss.