Steven Woolfe, a leading light in the UK Independence Party, collapsed after a fight at the European Parliament in Strasbourg. Earlier reports suggested Woolfe was seriously ill, but he said later he was "feeling fine."
A statement from Woolfe, issued a few hours after Thursday's incident, said he was feeling better but staying in hospital overnight for observation.
"The CT scan has shown that there is no blood clot in the brain. At the moment I am feeling brighter, happier and smiling as ever."
Thursday's dramatic events unfolded when Woolfe, who is the front-runner to be UKIP's next leader, was punched and hit his head at a party meeting at the European Parliament in Strasbourg, British media reported.
Images showed him face down on a walkway outside the EU legislature chamber after he fell and lost consciousness.
Interim Party leader Nigel Farage tweeted about the incident, describing how Woolfe "subsequently collapsed and was taken to hospital. His condition is serious," said Farage.
Fellow UKIP politician Neil Hamilton told the BBC that Woolfe had been "carted off to hospital with bleeding on the brain."
But a few minutes later, a Politico Europe reporter cited another UKIP MEP as saying that Woolfe was "conscious and recovering" in hospital.
Ongoing power struggle
Britain's Sky News cited a party source as saying that Thursday's altercation took place during talks to "clear the air," as several MEPs were unhappy that Woolfe had considered defecting to Britain's ruling Conservative party.
The European Parliament confirmed that emergency services were called to the parliament building at 12:40 pm local time (1040 UTC/GMT) on Thursday.
The incident came two days in to a leadership contest sparked by the resignation of UKIP's new leader Diane James after just 18 days in the post. James took over from long-time leader Farage, who stepped down in June.
After failing to apply in time to take part in the previous ballot, Woolfe had announced his intention to run in the upcoming leadership vote and was the bookies' favorite to win.
UKIP, a euroskeptic party, has the most seats in the European Parliament of any British political grouping, after winning 26.6 percent of the vote in the 2014 European elections.
The party was instrumental in getting Britain to hold a referendum on EU membership - or rather in frightening the center-right Conservatives into calling one to guard against further losses at home - which ended in a June 23 vote for Britain to leave the 28-country bloc.
Since the result, the always-fractious party has been torn by more infighting, which saw James stand down after little more than two weeks, citing personal reasons.
mm/msh (AFP, Reuters)