She was taken to hospital after overturning on a Southern California freeway, police said.
Officers found her Ford Explorer on its side on Highway 101, about 65 miles north of Los Angeles, shortly after 1300 (2000 GMT).
Miss Lewinsky escaped with scrapes and bruises and left hospital after treatment for minor abrasions.
A highway patrol officer said the accident happened after Miss Lewinsky suddenly realised she was too close to a motor home in front of her while trying to get something out of her purse.
The officer added that Miss Lewinsky had swerved to avoid an accident and lost control of her car.
Miss Lewinsky's affair with the president sparked the sex-and-perjury scandal that led to his impeachment.
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