HUY, Belgium (AP) _ Former world No. 1 ranked cyclist Francesco Casagrande pulled out of the Tour de France after the opening of the fourth stage Wednesday.

Casagrande, who rides for Fassa Bortolo, had been troubled by gastroenteritis since starting the Tour last week and had slipped behind race favorites Lance Armstrong and Jan Ullrich.

In the overall standings, the Italian was five minutes, 56 seconds behind race leader Stuart O'Grady at the beginning of Wednesday's stage.

He dropped out of the race soon after the start of the 133-mile fourth stage from Huy, Belgium to Verdun, France.

Casagrande fractured his arm during a fall in the opening stage of the Giro d'Italia in May.