Bastianelli is now set to miss the Beijing Olympics
Women's cycling world road race champion Marta Bastianelli has tested positive for a banned stimulant.
The 21-year-old, who won the world title in Germany last year, tested positive during the Under-23 World Championships earlier this month.
She was due to take part in the Beijing Olympics where she would have been up against Britain's Nicole Cooke.
But a spokesman for the Italian Olympic Committee (Coni) said her participation was now unlikely.
Italian Cycling Federation president Renato Di Rocco said they would ask for Bastianelli's B sample to be analysed.
"She has committed an incredible act of naivety, she tested positive for flenfluramina: a dieting product," he said. "She's obsessed with her weight, she eats only salad."
Marta Bastianelli has betrayed Coni, the (Italian Cycling) federation and the world of cycling
Coni president Gianni Petrucci
Bastianelli insists she is innocent and instead blamed her local pharmacy.
"I'm disgusted with my trusted chemist for preparing a mix of herbs for me aimed at weight loss," she said.
"Like always I wanted to read the list of products used and amongst them was benfluorex, which doesn't figure among the list of banned substances.
"However, laboratory analysis demonstrated that this product contains the ingredient responsible for my positive test.
"But how could I know that?"
Coni president Gianni Petrucci said his organisation would take a tough stance if Bastianelli's B sample proves positive.
"If the analysis is confirmed we will be unyielding," he said.
"Marta Bastianelli has betrayed Coni, the (Italian Cycling) federation and the world of cycling."