Children suffering from brain tumours are being given Thalidomide, the morning sickness drug that caused birth defects in 10,000 babies 50 years ago.
Some cancer sufferers prefer it to chemotherapy
Doctors say they have only given it to children under strict controls, and if all conventional treatments fail.
Thalidomide was withdrawn in 1961 after thousands of babies were born with no limbs or with stunted arms or legs.
It has since been used to kill cancer in adults but using it on children is very rare and only a handful have it.
Professor Richard Grundy, from the Queens Medical Centre in Nottingham, is one of those behind the new treatment.
He told BBC's Breakfast the problems caused in pregnancy were due to the way Thalidomide stopped new blood vessels being made in the limbs.
"We're trying to use those properties against the tumour to stop new blood vessel formation there," he said.
Grown-up children did not face the same risk, he said.
Robert Wadsworth, 12, from Breaston, Derbyshire replaced chemotherapy with Thalidomide to treat his brain tumour, said: "I used to feel terrible and now I just feel tired. And I've got my hair."
His parents said the tumour was still the same size but Robert, who lives near Derby, was much happier and more like his old self.