The 26-year-old singer was experiencing chest pain and discomfort in the breast implants which she had fitted last fall. "She had them checked out and all was OK, so she didn’t have to stay in," a friend tells PEOPLE.
Winehouse was last hospitalized in November following a reaction involving over-the-counter medication that mixed with other medication in her system.
Saturday's hospital visit comes as Winehouse settles back into life in Camden, London, following her relatively brief time living in the northern suburbs of Barnet. She has been working on and off on her third album and helping with the career of her goddaughter Dionne Bromfield, with whom she was out last week.