London ( CNN ) -- A second former personal assistant to Nigella Lawson made drug use allegations against the celebrity chef Tuesday as she testified at her own fraud trial . Francesca Grillo and her sister , Elisabetta , are accused of embezzling hundreds of thousands of pounds from Lawson and her ex-husband Charles Saatchi . Francesca Grillo said she had not seen Lawson take drugs . But she told the Isleworth Crown Court in west London she had seen repeated evidence of drug use . `` At the beginning of 2012 , there were a few episodes when she came down and she had white powder in her nostrils , '' she said of Lawson . `` She brushed it off and said it was makeup . '' Asked by her defense lawyer if that could have been the case , Francesca Grillo said it was `` too white to be makeup . '' Lawson told her that when she was working on a new book , she needed to stay up through the night , Grillo said . The former personal assistant told the court that Lawson would have a runny nose for long periods of time , even in summer , and that she would have mood changes , going from very nice to `` absent and grumpy . '' She also described finding rolled-up bank notes with traces of powder in Lawson 's handbag and seeing the remnants of cannabis use around the house . Grillo said she spoke to Lawson 's two children about her cannabis use . They told the former personal assistant that Lawson had trouble sleeping , so she would go downstairs and smoke with them because it helped her sleep . Elisabetta Grillo , in her testimony last week , also told the court that she had seen indications of drug use by Lawson but had never seen her take drugs . In her own testimony this month , Lawson confirmed she had taken cocaine half a dozen times , during two periods of her life , and used cannabis in the past . But she denied being a habitual user , saying , `` I did not have a drug problem , I had a life problem . '' Saatchi had said in an e-mail that Lawson had used drugs regularly , but in his testimony before the court last month , he backed off that claim . In the e-mail , which the defense shared with the court at a pretrial hearing , Saatchi wrote that the two assistants would probably `` get off '' because Lawson was using cocaine and marijuana on a daily basis and `` allowed the sisters to spend whatever they liked . '' Lawson lied in court , former aide says . Luxury goods . The two sisters are accused of spending large sums on luxury goods on company credit cards they were supposed to use for household expenses . Both sisters deny the fraud charge . Questioned by the prosecution about her spending Tuesday , Francesca Grillo insisted that Lawson had approved her purchases . She admitted to having dresses , handbags and shoes from designers including Miu Miu , Christian Louboutin and Gucci . The prosecution outlined the alleged top 50 unauthorized transactions by Grillo , including trips to New York and European cities such as Paris , Milan , Berlin and Antwerp , with significant purchases in exclusive stores . In response , Grillo variously said that the trips were authorized by Lawson or that she could n't remember the trip , who she went with or whether she was even on the trip herself . She suggested that other members of the family could have used her card . Grillo said that Saatchi had shouted , banged his fists on a table and threatened to `` destroy '' her when he accused her of fraud this summer . `` You do n't cross Charles Saatchi , everyone knows that , '' she said . Grillo said it felt `` like a personal vendetta '' against her . Elisabetta Grillo also said Lawson had authorized all her personal spending . Lawson 'ashamed ' of drug use , court hears .
NEW : Prosecution says Francesca Grillo spent company money on trips , shopping . Grillo tells the court she was not a flight risk and had no reason to spend her own money. Francesca Grillo and her sister Elisabetta deny defrauding Lawson and Charles Saatchi . Both sisters say that their spending on personal items was approved by Lawson .