A major centre of homeopathy will no longer be able to spend NHS money on the controversial practice.
The Royal London Hospital for Integrated Medicine - formerly the Royal London Homeopathic Hospital - will stop providing NHS-funded homeopathic remedies in April.
Homeopathy is based on the idea that "like cures like", but scientists says patients are getting nothing but sugar.
Campaigners said the move was "hugely significant and long overdue".
How homeopathic pills are made
Homeopathy is based on the concept that diluting a version of a substance that causes illness has healing properties.
So pollen or grass could be used to create a homeopathic hay-fever remedy.
One part of the substance is mixed with 99 parts of water or alcohol, and this is repeated six times in a "6c" formulation or 30 times in a "30c" formulation.
The end result is combined with a lactose (sugar) tablet.
Homeopaths say the more diluted it is, the greater the effect.
Common homeopathic treatments are for asthma, ear infections, hay-fever, depression, stress, anxiety, allergy and arthritis.
The NHS itself says: "There is no good-quality evidence that homeopathy is effective as a treatment for any health condition."
The Royal London Hospital for Integrated Medicine has a long history with homeopathy. It was founded as the London Homoeopathic Hospital in 1849 by one of the first doctors to practise homeopathy in Britain.
But now patient leaflets say: "From 3 April 2018, the Royal London Hospital for Integrated Medicine (RLHIM) will no longer be providing NHS-funded homeopathic remedies for any patients as part of their routine care."
The hospital is run by University College London Hospitals NHS Trust.
A spokeswoman for the trust said: "No NHS funding will be spent on homeopathic medicines at the RLHIM."
It is just the latest clampdown on NHS homeopathy.
It was banned in the Wirral in north-west England in 2016. And a consultation by the NHS England concluded GPs should not be routinely prescribing homeopathy
Simon Stevens, the chief executive of NHS England, has described homeopathy as "at best a placebo and a misuse of scarce NHS funds".
The Good Thinking Society, which has campaign for the NHS to stop spending money on homeopathy, said the latest move was "hugely significant, and long overdue".
Its project director, Michael Marshall, told the BBC: "This move means that London has now joined the vast majority of the country in consigning homeopathy to the history books.
"The only areas of the UK still wasting money on these disproven treatments are Bristol and Glasgow.
"Hopefully, sensible decisions will be made in those cities too, and we can finally move away from throwing limited NHS resources at these ineffective treatments."