The 53-year-old star of "The Taste" said during the trial of two former personal assistants accused of defrauding her and her ex-husband there were two periods in her life when she used cocaine and she has occasionally smoked pot, British newspaper the Guardian reported.
"I have never been a drug addict," Lawson, who also is a best-selling author, testified. "I have never been a habitual user [of cocaine]."
She said she used cocaine when her first husband, John Diamond, had terminal cancer and then in 2010 when she was "going through a very, very difficult time."
"I did not have a drug problem," she said. "I had a life problem."
Lawson, who said she went through counseling, said she smoked marijuana with her other ex-husband, Charles Saatchi.
"I have to be honest, I have smoked the odd joint," she said. "I found it made an intolerable situation tolerable."
She's off drugs now, she said.
Cannabis "is a false friend and not a good idea," she said. "I found the answer was in changing the situation and trying to create a tolerable situation for me and my family. I have to say, since freeing myself from a brilliant but brutal man, I'm now totally cannabis, cocaine, any drug, free."