CHICAGO (AP) - The Reverend Jesse Jackson is being treated at a Chicago hospital after experiencing severe stomach pains.

Jackson tells The Associated Press that he is feeling much better after being at Northwestern Memorial Hospital overnight. He says that doctors have told him he has viral gastroenteritis but are conducting more tests.

Jackson says he was campaigning and doing voter registration in Georgia earlier in the week when he began to feel ill after apparently becoming dehydrated. Back in Illinois, he entered the hospital Wednesday.

The 66-year-old civil rights leader says he isn't sure when he'll be released.

The federal Centers for Disease Control and Protection says viral gastroenteritis is an inflammation of the stomach and intestines and isn't considered serious for most people.