Charlize Theron always "really appreciated" marijuana.
The 42-year-old actress didn't experiment with "anything" until later in life, but the psychoactive drug was always something she enjoyed more than drinking alcohol.
She said: "I was a wake-and-baker for most of my life.
"I was older [when I first tried it]. I didn't really mess around with anything until I was much older. But I really appreciated marijuana way more than alcohol or anything else."
However, the 'Gringo' actress stopped using the drug in her early thirties when she realised it had made her "boring".
She added in an interview with E! News: "My chemistry was really good with it when I was younger and then it just changed one day.
"Like, in my early thirties I just became boring on it and I would just stand in front of my fridge, so that's no good.
"It totally changed, so I stopped."
However, the 'Atomic Blonde' actress - who has son Jackson, six, and two-year-old daughter August - isn't opposed to trying marijuana again to help her sleep.
She said: "I'm open to retrying it again because now there's all these different strains and you can be specific with it.
"I'm actually really interested because I have really bad insomnia, and I'd much rather get off sleeping pills and figure out a strain that helps me sleep better.
"So when I have a moment, I'm actually doing that with my mom. My mom has really bad sleep too."
Charlize previously spoke about experimenting with various illegal substances in her twenties.
When asked if she did cocaine in her youth, she said: "I definitely experimented, yeah," and referring to ecstasy, she added: "I had a f***ing great time. I didn't do a lot of it but I definitely did in my twenties.
"I always worried in my twenties I would feel like if I had kids I would be missing out on this life and then I hit my thirties and thought I am so f***ing done with it."