Massachusetts Sen. Edward Kennedy was hospitalized briefly after a "mild seizure" Friday, his office announced.
Kennedy was taken to a Cape Cod hospital by a Fire Department rescue squad after a 911 call about 5 p.m. Friday, a local police spokesman said Friday.
"Doctors believe the incident was triggered by a change in medication," the statement from his office said. "Senator Kennedy will return home tonight and looks forward to watching the debate."
Kennedy was described as alert and conscious when the emergency team arrived at his home in Hyannis Port, Sgt. Ben Baxter of Barnstable Police Department said.
Kennedy spent several hours in the hospital before being released.
The veteran Democrat had surgery for a brain tumor in June and has made only a handful of appearances since then, including a triumphal speech on the first night of the Democratic National Convention last month.
Kennedy, 76, is currently undergoing radiation treatment and chemotherapy. His office has said he expects to return to the Senate in January.
In August, Kennedy electrified the crowd at the Democratic National Convention, pledging to see Barack Obama elected president.
His convention appearance came at his own insistence, over the advice of associates worried about the effects on his health, a Democratic source close to the Kennedy family said.
The liberal icon was "itching to go and pushing back" at those who said the trip was too risky to make, the source said.