"You're not on any prescription drugs?" Winfrey pressed.
"No, no," Lohan insisted, then checked herself: "I take Nexium. Because I have acid reflux."
Clad in a form-fitting orange dress, Lohan said a comfort level with her past chaotic life had fed her much-reported partying and her brushes with the law. But she added that she takes full blame for her mistakes.
When Winfrey asked if she can turn her life around this time, Lohan said with no hesitation, "Yeah."
The interview aired as an episode of "Oprah's Next Chapter" on the Oprah Winfrey Network, which will spotlight Lohan next year in an eight-part docuseries based on her life.
During the hour, an advertisement appeared for Cliffside Malibu, the rehab facility where Lohan was recently residing. That ad boasted of a treatment program so successful, it's guaranteed.