"It reminds me of my dad," she said. "I took it four times in a period from about the age of 20 to 23, and I got caught twice."
Cocaine made her feel "a little too buzzed -- it made me feel uncomfortable," she told Morgan.
She's not "a junkie," she said. "It's the truth. I've never taken heroin either, never injected myself with anything, never done LSD. Those things all scare me."
Her drugs of choice are "pot, obviously, and Ecstasy," she said. "I liked that (Ecstasy) better than the others." Morgan reports Lohan then giggled.
Lohan: Not a junkie
Lohan has previously acknowledged having a drug problem, though. She posted this Twitter message in September 2010 just before entering the Betty Ford Clinic for three months: "Substance abuse is a disease, which unfortunately doesn't go away over night. I am working hard to overcome it and am taking positive steps."
Lohan claimed to Morgan that she's just misunderstood. The constant online tabloid reports of late-night partying, which sometimes results in legal issues, don't show the real person.
"I've never been a junkie, and never will be," she said. "I just like going out late to clubs with friends and listening to music. Always have done. It's not that unusual for girls of 26!"
Heath Ledger's advice
She slowed down on her drinking on the advice of an actor, Lohan said.
"Heath Ledger told me to give it up for a year because he'd just done that, and so I did, and it wasn't a problem for me," she said. Ledger was 28 when he died from a prescription drug overdose in January 2008, a year after Lohan's first rehab visit.
Lindsay prefers men
Lohan also talked to Morgan about her sexuality -- she's straight despite a past relationship with a woman. "I like boys," she said.
"I know I'm straight," she said. "I have made out with girls before, and I had a relationship with a girl. But I think I needed to experience that and I think I was looking for something different."
She said she was in love with Samantha Ronson during their relationship, and "I still love her as a person."
"I like being in a relationship with a guy," Lohan said. "But there's something just different about it with a woman. When I was with Samantha, I didn't want to leave, because I didn't want to be alone. It was very toxic."
Dad 'creates chaos'
About her father, Michael Lohan: "He won't change," she said. "I just think there comes a point where you just kind of have to accept what it is.
"Whenever I do try to bring him back into my life, he creates chaos for me and uses it to his advantage. He's been really good and then really crazy my whole life."
While she blames the Los Angeles lifestyle for steering her off course, she does point to two Hollywood women who have helped her.
"Meryl Streep was nice," Lohan said. "She just advised me on my acting and what I needed to do differently, and she told me I needed to go back to live with my mum for a while."
She couldn't move back to New York because at the time, her probation requirements, which including regular drug testing, restricted her to California -- "the worst possible place I could be," she said.
"Jamie Lee Curtis was very kind to me, too," she said. "She also told me to listen to good advice and to get rid of the hangers-on."