A 20-year-old woman was head-butted and then kicked and punched at Eastern Promise, in High Street, March, at about 2am on Sunday, November 29.
The attacker, a woman in her 20s, was with two other women who also joined in the assault.
The victim received hospital treatment for serious injuries and has since been released.
There were other people inside and outside the takeaway at the time and officers are urging them to come forward.
Anyone with information should contact DC Mark Yendley, at Wisbech Police Station, on 101, or Crimestoppers, anonymously, on 0800 555 111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here