The cause of death of actress Hayden Panettiere has been officially confirmed more than a month after she died at the age of 36.

The Heroes, Nashville and Scream star died on August 16, 2026, after she was found unresponsive at an apartment in Greenville, South Carolina.

The Greenville County Coroner’s Office has now determined that Panettiere died from the toxic effects of several substances, including fentanyl. Her death was officially classified as an accident.

Coroner Confirms Cause of Death

According to the coroner’s findings, Panettiere’s cause of death was the toxic effects of fentanyl, 4-ANPP, alprazolam, methocarbamol and quetiapine.

4-ANPP is a chemical byproduct associated with fentanyl production. Alprazolam is commonly known by the brand name Xanax and is used to treat anxiety and panic disorders. Methocarbamol is a muscle relaxant, while quetiapine is a prescription medication used for several psychiatric conditions and can also be prescribed for sleep-related problems.

The coroner’s office said an autopsy found “no signs of trauma … that would have contributed to the death.” The manner of death was ruled an accident.

Panettiere Was Found Unresponsive in August

Panettiere was found unresponsive at the Judson Mill Lofts apartment complex in Greenville on August 16.

Emergency responders were called to the property after an acquaintance placed a 911 call. According to the Greenville County Coroner’s Office, advanced resuscitation efforts were carried out, but Panettiere was pronounced dead at the scene.

Her death initially prompted questions about what had happened because authorities did not immediately release an official cause.

Reports subsequently revealed that investigators had been examining possible drug-related circumstances surrounding her death.

Police Say There Was No Initial Sign of Foul Play

The Greenville Police Department said its preliminary investigation did not indicate signs of foul play or suspicious circumstances.

Police stated:

“The preliminary investigation has not indicated any signs of foul play or suspicious circumstances.”

The department has nevertheless continued investigating the circumstances surrounding Panettiere’s death.

The Drug Enforcement Administration has also been investigating questions surrounding the source of the fentanyl, according to ABC News.

Family Representative Says Investigation Is Ongoing

Although the coroner has established the medical cause and manner of death, Panettiere’s representatives have indicated that questions surrounding the circumstances remain.

Her family publicist, Kasey Kitchen, told The Associated Press:

“the investigation is still ongoing and the case is complex.”

The statement came after officials released the toxicology findings and classified the death as accidental.

Her Mother Speaks About Addiction and Recovery

Panettiere had spoken publicly about her struggles with addiction and recovery during her lifetime.

Following the coroner’s announcement, her mother, Lesley Vogel, described her daughter as someone who had continued fighting through those challenges.

Vogel said:

“Hayden was a fighter. … She was transparent with her addictions and her numerous rehab attempts show her resolve to live a healthy life.”

She also said that the accidental-overdose ruling did not remove questions about the source of the drugs involved.

“The loss of Hayden is palpable; grief permeates the soul and it will live with those who loved her forever. … Everything moving forward will be healing but the mission is and will always be justice for Hayden,” Vogel said, according to ABC News.

A Career That Began in Childhood

Panettiere began working as an actress when she was a child and eventually became one of television’s familiar young stars.

She appeared in commercials as an infant and later took roles in television soap operas, including One Life to Live and Guiding Light.

Her early film work included providing the voice of Princess Dot in A Bug’s Life. She later appeared in Remember the Titans, helping establish herself as a young Hollywood performer.

Her breakthrough television role came with the science-fiction drama Heroes, where she played cheerleader Claire Bennet.

She subsequently gained another major following through the country-music drama Nashville, in which she portrayed Juliette Barnes.

Panettiere also appeared in the Scream film franchise, further expanding her film career.

Panettiere Had Spoken About Addiction and Recovery

Before her death, Panettiere had been open about her experiences with addiction, recovery and postpartum depression.

Her memoir, This Is Me, addressed aspects of her personal life and the challenges she faced away from the screen.

She had also entered rehabilitation during her time working on Nashville as she sought help for addiction.

The actress had previously discussed the difficult consequences of her struggles and her efforts to rebuild her life.

Memorial Held for the Actress

Panettiere was remembered at a memorial service in California following her death.

Her representative confirmed the gathering, which was attended by people from across her Hollywood career. Among those photographed at the memorial were Nashville co-star Connie Britton, Evan Ross and Ruby Rose.

Panettiere’s death at 36 brought renewed attention to the difficulties she had publicly discussed throughout her life, particularly addiction and recovery.

The official coroner’s findings have now established the immediate medical cause of her death as toxic effects from fentanyl and the other substances identified in her system, while authorities continue to examine the broader circumstances surrounding what happened.