A US woman who had a face transplant in 2011 after being attacked by a chimpanzee is back in hospital because her body is rejecting the tissue.

Charla Nash had agreed to take part in a military-funded experiment to see if she could be weaned off the anti-rejection drugs she had been taking since her operation.

But the Connecticut woman says doctors at Boston’s Brigham and Women’s Hospital have now decided to end the experimental drug treatment.

Nash speaks to the media at the Legislative Office Building in Hartford

Ms Nash said she would appreciate any prayers

They plan to put her back on her original medication in the hope of reversing the problem.

Dr Bohdan Pomahac, director of plastic surgery transplantation, said Ms Nash is doing well.

Boy who had face ripped off by chimpanzees recovers from surgery

He said that she is experiencing a “moderate rejection episode, which face transplant patients experience on occasion”.

The doctor said he expects the episode to be resolved within the coming week.

Ms Nash would be discharged from the hospital in the next day or two, he predicted.

She said she would appreciate any prayers.

Ms Nash said her role in the experiment may aid research into treating disfigured soldiers returning from war.

She was mauled by a neighbour’s chimpanzee in Stamford, Connecticut in February 2009.

She was helping the woman lure the 200lb (91kg) pet ape, Travis, back into her home but the animal went berserk and ripped off Ms Nash’s nose, lips, eyelids and hands before being shot dead by a police officer.

Ms Nash reached a settlement with the estate of the chimp’s owner, Sandra Herold, who died in 2010.