Nigella Lawson denied stashing cocaine in a hollowed-out "fake book" alongside rings she exchanged with her late husband as she gave evidence in the fraud trial of her two former personal assistants.
The TV chef, who has admitted using the class A drug in the past, was accused of the "very regular use of cocaine" which "escalated in the last five years" by Barrister Karina Arden, representing one of the defendants.
"That is categorically not the case," Ms Lawson replied.
Under cross-examination at Isleworth Crown Court in west London, Ms Lawson said she had "never knowingly" met a drug dealer or exchanged money for cocaine.
Asked whether "dealers were turning up at the house", Ms Lawson replied: "No."
She denied keeping cocaine in a hollow book alongside jewellery from her mother and two grandmothers.
The jewellery box also contained wedding rings she exchanged with her late husband John Diamond, including one he received after being diagnosed with terminal cancer, the court heard.
Ms Lawson's daughter and a friend discovered the box containing cocaine and called Francesca Grillo, who "tried to make up some sort of excuse to cover your back", Ms Arden said to Ms Lawson.
"No, I have never heard that," she replied.
The food writer was "in a high state of panic" after the book went missing when she moved house, Ms Arden added.
"I was in a high state of anxiety because I thought I had lost my late grandmothers' and late husband's jewellery and wedding rings," Ms Lawson replied.
"It does not need embellishment."
Ms Lawson said it was "completely wrong" to suggest that she frequently came downstairs at her home with white powder on her face or had a constant runny nose.
As questions of her drug use continued, Ms Lawson said:
Jurors were previously read an email sent to Ms Lawson from Charles Saatchi in which he said the defendants would "get off" on the basis that she was "so off her head" on drugs she allowed them to "spend whatever they liked".
Ms Lawson has also accused her multi-millionaire ex-husband of "peddling" stories about her alleged drug habit, including that he was checking her nose for cocaine when he was photographed holding her throat outside Scott's restaurant in central London.
She said one of the reasons she did not start libel proceedings against Mr Saatchi was because she "can't afford it".
"I don't have a substantial fortune," she said.
Francesca Grillo, 35, and her sister Elisabetta, sometimes referred to as Lisa, 41, are accused of committing fraud by abusing their positions by using a company credit card for personal gain.
Prosecutors claim the Italian sisters lived the "high life", spending the money on designer clothes and handbags from Louis Vuitton, Christian Dior and Vivienne Westwood.
The pair are accused of using credit cards loaned to them by the TV cook and her ex-husband Mr Saatchi to spend more than #685,000 on themselves between 2008 and 2012, the jury has heard.
The Grillo sisters, of Kensington Gardens Square, Bayswater, west London, deny the charge against them.
The trial was adjourned until Tuesday.