She made the revelation during an appearance on "Jimmy Kimmel Live!", reports people.com.
"I'm always willing to try anything. You got one life to live, why not? I have really bad sleep (patterns) and so does my mom. We do take sleep medication and I was saying to her, 'Maybe we should try a sleeping strain, something that could help us with sleep'," Theron said.
Theron said she never expected her mother to be the one to shop for it.
"I really thought I would be the responsible one to have to go and get that. Last week she showed up at my house, literally drove in her little tennis outfit and brought me a little container and just left it on my kitchen table.
"She was like, 'So I got some blueberry covered chocolate ones but if you want it faster acting you should go for the mints those you suck and it works faster.' I assumed because she was in a tennis outfit, she had scored with one young tennis friend. Because she plays tennis with these really cool young girls," she said.
It was during the premiere of her film "Gringo" here that Theron learned where her mother really got the edibles from.
"She said, 'I went to the store by myself'," Theron said, as marijuana is now legal in California.
"I have this image of her in the store. She's just not this kind of person and buying marijuana she had like a full experience."
But she said it "totally works" for their sleeping patterns.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)