By Nick Triggle
BBC News health reporter
Arsenal striker Robin Van Persie has flown to Serbia for a novel form of treatment - placenta fluid is to be dripped on his injured ankle. Why is he doing this and will it work?
Van Persie has been a key player for Arsenal this season
It is not unusual for sports starts to look for super cures for their injuries.
England footballer Wayne Rooney used an oxygen tent prior to the 2006 World Cup to help him recover from a broken foot and six years ago runner Paula Radcliffe rubbed oil from the belly of an emu to ease injuries sustained in a collision with a cyclist.
But the news that Arsenal striker Robin Van Persie is heading to Serbia to get placenta fluid applied to an ankle injury has astonished many.
The 26-year-old hurt his ankle while playing for the Dutch national side in a match against Italy.
He was left with torn ankle ligaments after a challenge 10 minutes into the contest.
Scans revealed a partial tear would keep him out of action for six weeks.
But a Dutch journalist close to the national squad said he could be back in as little as four weeks if the treatment works.
TV and radio reporter Rob Fleur said a woman who specialises in the treatment had been recommended to Van Persie by former team-mates Dutch midfielder Orlando Engelaar and Serbian forward Danko Lazovic.
They both claim to have had rapid recoveries from similar injuries after travelling to Belgrade to see the specialist.
Van Persie, speaking before travelling out to eastern Europe on Monday, was hopeful despite being unsure what to expect.
He said: "She is vague about her methods but I know she massages you using fluid from a placenta.
"I am going to try.
"It cannot hurt and, if it helps, it helps.
"I have been in contact with Arsenal physiotherapists and they have let me do it."
Health benefits have long been associated with placenta.
Some studies have suggested eating it can reduce the risk of post-natal depression, while Turkish researchers found injecting placenta cells into rabbits helped them recover from fractures.
It is not known how the placenta may help - and more research is now being carried out.
However, it does have a high nutritional content.
In the animal kingdom mothers routinely eat the placenta to help them recover from the exertion of birth and there are anti-ageing creams on the market that use sheep placenta cells.
It seems likely that Van Persie's treatment will involve some form of massage using the fluid.
HEALTH BENEFITS OF PLACENTA
The placenta supplies food and oxygen to the foetus as well as releasing hormones to maintain pregnancy
Animals routinely eat their placenta, which is discharged after birth, to get nutrition following the exertion of labour
Some reports have suggested eating it could help ward off post-natal depression
In Peru, dried placenta has been given to children when they fall ill in the belief it will help cure infections
Turkish researchers have also used placenta cells to help heal fractures in tests on rabbits
But while the nutritional content of the placenta is known to be high, it is still not known exactly how it can aid the healing process
Such therapies are pretty standard for ligament damage.
Abbie Turner, manager of Bristol University's Sports Medicine Clinic, said: "If it is a low grade ligament tear, treatment would nclude deep tissue massage and rehabilitation to restore balance and strength to the affected joint, ultrasound, joint mobilisations and strengthening exercises to strengthen weakened muscles around the joint.
"If a tear is very serious then surgical repair can sometimes be required.
"More alternative treatments are sometimes used with success and these can include acupuncture and joint injections.
"But I have never heard of this - and I won't be rushing out to use it on my patients."
Instead, she believes the steps taken by Van Persie and other stars reflects the nature of top-level sport.
"High-level sportsmen and women will try many alternative treatments, often in a response to return to play or training as quickly as possible.
"This can sometimes be due to financial pressure as is often the case in football."