BBC News Online health staff
Each week Hilary Day, aka Dr Doppit, does her ward rounds at Southampton's General Hospital.
Most children love the clowns
But instead of a stethoscope and a white coat, Hilary is more likely to be found carrying balloons and magic tricks.
For Dr Doppit is one of the hospital's two resident clowns.
After studying drama at university, Hilary started doing children's drama and was soon bitten by the bug.
When she saw an advert for a 'clown doctor' advertised in The Stage newspaper she was certain she had found her perfect job.
"My forte was children's theatre and when I saw the advert it was like the penny had dropped.
"And I thought all these things I have done have led to this.
"The job is the most rewarding I have ever had.
"I came from a family of nurses, my mother was a nurse and my grandmother was a nurse. So the caring profession is in my blood."
Hilary and her partner, Dr Geehee, did four weeks training, learning how to do magic tricks and balloon modelling, as well as basic courses in children's psychology, hygiene and infection control.
Each week she does about three afternoon shifts at the hospital, starting with a meeting with the medical staff.
The clowns need to know where medics want them to visit and which patients will benefit most from a visit from Dr Doppit and Dr Geehee.
Their first stop is outpatients where the patients are generally less sick and then it's off to the wards.
But Hilary stressed that none of the clowns would approach a child without being invited to and that if the child asked them to leave they would do so immediately.
"You learn quickly to pick up on the mood of each individual.
"Obviously in intensive care it is a very different approach, much gentler. Some children don't want to see you and others don't know what is going on."
But she said that other children were delighted when they saw the clown.
"One day when I was working in Great Ormond Street Hospital I was taken to see a little girl who was very excited. She hugged me and she kept saying to the nurses 'thank you, you have brought me my own clown'.
"90 percent of children see a clown and are overjoyed, but there are others who are feeling too ill or rough and then there are some who are afraid of clowns.
"I always ask them if they want you to come in and see them.
"We will then do magic for them, make balloon shapes and tell stories, or juggle. My partner does origami. It is just general silliness."
Hilary said the job had some fantastically rewarding as well as some very sad moments.
"There was this little boy in the specialist centre that we visit for severely epileptic children and I spent a long time playing for his benefit, but he did not want to be involved. Then out of nowhere he hugged me and rested his head on my shoulder. All the staff were amazed, because they said he does not connect with adults."
But she said that there were lots of sad cases too, including the parents she had met in a waiting area holding toys.
"I asked them where their child was and they said he had died.
"You just feel you want to take all the pain away. Laughter is the best medicine, but there is only so much you can do."
Hilary is employed by the Theodora Children's Trust, which also has clown doctors working at a number of other UK hospitals.
Joanie Speers, executive director of Theodora Children's Trust said clowns helped to bring normality back to the sick children.
"Children in hospital, whether they are long-term or terminally ill, or just in for a routine operation, are excluded from their normal routines, from their school and social life and from their family environment.
"They are not only vulnerable and possibly frightened and homesick, but also very often bored.
"Regular visits from Theodora clown doctors can put some of the 'normality' back into their lives, and have been shown to make a big difference on their recovery and rehabilitation.
"Both the anticipation and the memory of the visits can play a big part in how the children feel about themselves.
"We also know that humour can have a positive impact on a person's health - laughter produces endorphins which basically make you feel better.
"It makes you relax and allows things to happen, or in the case of children, can help make them responsive to treatment, or even just communication."