NHS England has announced a crackdown on the treatment of "minor" ailments such as dandruff and diarrhoea.
Thirty-five treatments responsible for £570m of spending have been targeted.
All are available over-the-counter in pharmacies. And the restriction will apply only where the ailment is judged to be a minor, short-term problem.
NHS bosses says the move could cut spending by a fifth. But experts warned the poorest risked losing out on treatment.
While the new rules, which apply from April, allow doctors to issue prescriptions where for a long-term ailment or one related to a more serious condition, the Royal Pharmaceutical Society said those on low incomes could still end up being denied drugs "because of their inability to pay".
And Andrew McCracken, from the National Voices patient group, urged GPs to use their "medical judgement" and prescribe treatments when people could not afford to buy them.
The treatments targeted include those for:
- athletes foot
- mild acne
- head lice
- cold sores
NHS England chief executive Simon Stevens said: "Every pound we save from cutting waste is another pound we can then invest in better [accident and emergency] care, new cancer treatments and much better mental health services."
And Dr Graham Jackson, of NHS Clinical Commissioners, which represents local health managers, said unfortunately "difficult decisions" had to be made.
The move follows a similar measure last year, which saw the NHS stop paying for things such as gluten-free food and suncream.