The 38-year-old television personality said on Sunday's episode of Busy Tonight that Jenner worried she would become a "crazy drug addict' after she did ecstasy when she was younger.
"I would tell my mom everything. We always had such a close relationship, so I would come home and be like, 'Oh my God, mom, I did ecstasy last night,'" she told host Busy Philipps.
Kardashian said she ultimately quit using drugs after one particularly impactful conversation with her mom.
"She was like, 'You, one day, you're not going to be able to have babies, you can't do this, you're going to ruin yourself!' Like, she was so upset," the star recalled. "She was so upset thinking I was going to turn into something and just be this crazy drug addict."
"I was just like, 'You know what? She's so right, I'm so over it. Like, this is so not me.' And I just never did anything again," she said.
Kardashian said in the Nov. 25 episode of Keeping Up with the Kardashians that she was high on ecstasy when she married Damon Thomas in 2000. She was also on ecstasy when she filmed her infamous sex tape with Ray J.
"I did ecstasy once and I got married," the star said. "I did it again, I made a sex tape. Like, everything bad would happen."
Philipps underwent a full Kardashian makeover last week in honor of Kardashian's appearance on her show. The actress said she spent four hours in hair, makeup and wardrobe to become a Kardashian lookalike.