Decorating children's wards with paintings of clowns to create a nurturing atmosphere could backfire, research suggests.
Some children think that clowns are "frightening and unknowable"
A University of Sheffield study of more than 250 children, aged four to 16, found the images were widely disliked.
Even some of the oldest children found the images scary.
The researchers said the findings, reported in Nursing Standard magazine, highlighted the importance of consulting children in hospital design.
Researcher Dr Penny Curtis said: "As adults we make assumptions about what works for children.
"We found that clowns are universally disliked by children. Some found them quite frightening and unknowable."
Dr Curtis stressed the importance of consulting with children - who like colourful spaces and references to contemporary culture - when designing or changing the hospital environment.
She added that wards tended to be designed to meet only the needs of the youngest children. As a result older children often felt hospital space was not for them, raising the risk that they would be passive and inactive.
Marjorie Gillies, a senior nurse for patient services at the Royal Hospital for Sick Children in Glasgow, said: "We found that having clowns and decorations everywhere is too much.
"We have gone back to plain walls with areas decorated appropriately."
A different era
Patricia Doorbar is a child psychologist in North Wales who has carried out research into children's views on healthcare and art therapy.
She said: "Very few children like clowns. They are unfamiliar and come from a different era. They don't look funny, they just look odd.
"Children are much more happy with things stuck on the wall that have some sort of personal relevance for them, not images that are foisted upon them by adults."
Mrs Doorbar said decor, and, in particular, colour, had an important role to play in aiding the healing process. It was key that children should be able to feel safe.
"My research has shown that children in hospital are often frightened by a lot of things that adults would not find scary.
"For instance, some children thought they were being moved to a side room because they were going to die."