You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
"The actress was not seriously injured and is resting comfortably at home," her spokeswoman said in a statement.
No further details were available. Santa Monica is a community immediately adjacent to Los Angeles.
Witherspoon, 35, became a box office sensation and A-list Hollywood star in her Legally Blonde comedy movies, and she won an Academy Award for best actress in drama Walk the Line.