The Ugly Truth star apparently grabbed a broom and ran towards the wild animal in a bid to save her small dog.
A friend of the actress told the National Enquirer: "A savage coyote sank its teeth into one of Katherine's small dogs. She heard her pet howling and growling in the backyard and ran out to discover the coyote had gripped her beloved dog in its slathering jaws."
They continued: "Screaming, she snatched a broom and ran at the beast, which instantly dropped its whimpering prey and streaked into a bush."
Heigl's dog was reportedly shaken but didn't suffer any serious injuries. The insider said: "Her dog yelped in terror and instantly bounced back on its four feet, lucky to be alive. It sustained two small puncture wounds."
Heigl has previously admitted that her husband, musician Josh Kelley, has begged her to stop bringing stray dogs home.