The official cause of death has been confirmed for Hayden Panettiere. The Greenville County Coroner’s Office in South Carolina has determined Panettiere died from the toxic effects of fentanyl, 4-ANPP, Alprazolam, Methocarbamol, and Quetiapine. The manner of death has been ruled accident.
Source: [Deadline](https://deadline.com/2026/09/hayden-panettiere-cause-of-death-confirmed-fentanyl-1237110035/)