The famously clean-living actress has spoken about her close friend Courtney Love's battle with illegal substances, hinting she has also experimented with drugs.
Speaking about Courtney, Gwyneth told Britain's Elle magazine: "I don't think she's on Class A narcotics anymore. Maybe just Class C. That's no big deal - aren't we all, ha, ha, ha!"
At the time of the interview, Class C drugs included cannabis, ketamine and other tranquillisers. Gwyneth also admitted she misses smoking and often indulges in red wine and Guinness.
She said: "Man, I wish smoking didn't kill you. I'd be smoking right now. I miss it. "I'm probably less square than people think. I never get drunk to the point of throwing up. But I get very talkative."
The actress refused to reveal details about her relationship with her husband, Coldplay frontman Chris Martin. Asked why they are never photographed together, Gwyneth - who has two children with Chris - replied: "It doesn't behove us to be a public couple. He certainly doesn't want to be that. I mean, we've never walked down a red carpet together, and we never will."
Gwyneth describes Chris as a "good, good man", admitting she is "amazed" he didn't leave her after her father Bruce Paltrow died of pneumonia in 2002. She explained: "I'm amazed he stuck with me, because I was a wreck. To this day I'm faced with his death all the time. I've had pneumonia twice in the past year, and that's ultimately what he died of. I've been dealing with my own fear of death - every time I get a cold."
Gwyneth became obsessed with healthy eating after Bruce's death and believes a better diet could have helped her father, who had radiotherapy for oral cancer before he contracted pneumonia. She said: "I met a macrobiotic counsellor who was dying from cancer and she cleared herself. She said he had to detoxify otherwise the cancer would return. And it did. I believe there's a direct correlation between environmental toxins, preservatives in food, and disease."
The 36-year-old actress went on to slam critics of her website GOOP - which includes tips on how to lead a healthy lifestyle - insisting she is trying to help people by offering advice. She added to Britain's Elle magazine: "F**k the haters! I'm a good person and I'm trying to put good things into the world."