Doctors who have performed what they claim is the world's first successful tongue transplant say the patient is in excellent condition.
The operation took place at Vienna General Hospital
The team of doctors from Vienna's General Hospital held a press conference on Tuesday to give further details of the groundbreaking operation, which took place on Saturday.
They said the patient is awake and doing better than had been anticipated.
Blood appears to be circulating normally in his new tongue and there has been no sign of him rejecting the organ.
The 42-year-old man, who has not been named, had been suffering from a malignant tumour in his mouth.
This meant that his tongue had to be removed. Surgeons spent 14 hours removing the diseased organ and attaching a new tongue.
Dr Rolf Ewers, who lead the operating team, said they hoped that with his new tongue the patient would be able to talk and eat as normal.
However, at present he cannot move the tongue, and he is unlikely ever to regain his sense of taste.
The risk of infection remains high and the man is currently in intensive care. The first two weeks after surgery are the critical period.
Professor Ewers said he hoped the operation would become a normal undertaking over the next few years.
"This is the next step for better treatment for patients. The liver and kidneys are complicated organs, but the tongue is just muscle, so it should work out."
Professor Claus Krenn, who is monitoring the patient in intensive care, said it was difficult to assess the success of the transplant, as the tongue had no vital function.
"We have to rely on blood flow - whether the organ looks nicely coloured."
Professor Krenn said one of the biggest potential dangers was the risk that the patient might bite into the transplanted organ.
Tongue transplant surgery has been carried out before, but only in animals.
One of the major problems facing doctors is that the mouth is continually being filled with foreign - and potentially infectious - material. However, the mouth is very effective at keeping itself clean naturally.
Doctors often turn to muscle tissue taken from a patient's small bowel to rebuild a tongue that has been amputated because of cancer or other disease, but they say this method is far from ideal because the artificial tongue has limited function.
Dr Peter Rowe, chairman of the ethics committee of the British Transplantation Society, told BBC News Online that the crucial issue would be whether the donor organ could provide the recipient with sufficient mobility.
He said: "A lot of immuno-suppressant therapy would be required to promote acceptance.
"One would have to weigh up the benefits of a transplant with the various risks of suppressing the immune system, which raises the risk of infection, and, in the long term, of further malignancies."