The actress, who plays barmaid Sam Mitchell, was taken straight to hospital in London after returning to the country earlier than expected.
She is "in high spirits" and delighted to be back in the UK, the show's makers have said.
She is likely to be away from the hit TV soap for at least a month - but producers still do not know when she will be well enough to return.
This is likely to disrupt filming as she only had two weeks booked off work for her holiday.
Medcalf broke her leg, hand and a breast bone when she and her boyfriend were on their way to Italy from Calais on the first day of their holiday.
Other cast members will visit her during the next two weeks, a BBC spokesman said.
On Wednesday, a spokesperson said: "The main priority is that she gets better and doesn't even think of returning to work until she's recovered."
Controversial
Medcalf joined EastEnders in January 2002, replacing Daniella Westbrook.
Her character Sam was dragged back to the BBC One soap's Albert Square after being found by her mother working as a topless waitress in Spain.
Sam - formerly known as Sam Butcher when married to her childhood sweetheart Ricky - has a reputation for taking off suddenly, only to reappear out of the blue.
The character has had a couple of controversial storylines involving relationships with men, including a fling with Steve Owen, who was played by Martin Kemp, and a flirtation with the boyfriend of Sharon Watts, played by Letitia Dean.