Actress Skye McCole Bartusiak, who memorably portrayed Mel Gibson's daughter in “The Patriot,” died of an accidental drug overdose, the Harris County Institute of Forensic Sciences confirmed to FOX411.

Bartusiak’s mother, Helen Bartusiak, said at the time of her death, the actress had been living in a garage apartment at her parents’ home. She said the actress’ boyfriend found her unresponsive on her bed on July 19.

The Harris County Institute of Forensic Sciences told us her death was a result of “combined toxic effects of hydrocodone and difluoroethane with carisoprodol.” Difluoroethane is a chemical that is typically inhaled.

PHOTOS: Recent celeb deaths

Bartusiak made her acting debut in the television miniseries “Storm of the Century” in 1999 and also had a role on "24" in 2002-2003.

More On This...

She made her film debut in the “The Cider House Rules” in 1999 and starred with Michael Douglas in “Don’t Say a Word” in 2001. Her most recent move was “Sick Boy” in 2012.

Bartusiak was best known for her role in Gibson’s 2000 Revolutionary War epic, where she played the daughter of militia leader Benjamin Martin who struggles to speak with her father.

“The Patriot” cast also included Heath Ledger, who died after an accidental overdose of painkillers and sedatives in 2008.

Click here to see a clip of Bartusiak in 'The Patriot'

The Associated Press contributed to this report.