Britney Spears claims using an asthma inhaler is to blame for her positive drugs test.
The 'Toxic' singer, whose court-ordered urine sample returned a positivereading last week, denies any illegal substance abuse and insists the drugthat showed up was Albuterol, which is asthma medication.
However, sources claim the class of drug that showed up was an amphetamine and Albuterol is not an amphetamine.
It was also recently reported Britney doesn't suffer from asthma and wasallegedly using the inhaler as a weight-loss aid.
The troubled star has to undergo random court-ordered drugs tests as part of the custody arrangements for her two sons with ex-husband Kevin Federline.
Meanwhile, Britney's lawyer has defended the 25-year-old star for drivingthrough a red light with her sons, Sean Preston, two, and 14-month-oldJayden James, in the back of the car.
Sorrell Trope said, "Ms. Spears was being mobbed by paparazzi at the time. She was distracted. This was not blatant irresponsible driving on her part."
Kevin's attorney Mark Vincent Kaplan has requested Britney should not beallowed to drive when she is with the children.
Britney is currently allowed two monitored daytime visits with her sons and one overnight stay.