Customs officials and local police arrested Frigo's wife Tuesday with about 10 doses of the banned endurance-boosting hormone EPO. An Albertville prosecutor was due to question the couple Wednesday afternoon.
Frigo, of the Fassa Bortolo team, was 52nd in the Tour de France standings after Tuesday's 10th stage.
Tour director Jean-Marie Leblanc confirmed Frigo's wife was arrested near Chambery with what he called pharmaceutical products. He said tour officials don't know what the products are. Frigo was arrested Wednesday morning at the team hotel and is now in detention, Leblanc said, adding that the police "is doing its work."
The couple could face up to three years in prison and a fine worth twice the value of the banned products, if accused and convicted of importing and holding banned products.
Leblanc said Frigo is "a recidivist" who has had run-ins with the police and anti-doping controls. He said drug cheats need to be expelled.
"If the accusations are confirmed, Frigo would show that he's part of this generation of riders who have understood nothing, who didn't want to listen," Leblanc said.
Team spokesman Andrea Agostini said Frigo's arrest did not involve other members of the team.
"This affair only concerns Dario Frigo, and not the team," Agostini said.
Frigo was accused last year along with nine other cyclists and two physical therapists in Italy in connection with a drug scandal at the 2001 Giro d'Italia. The case is pending.
The 31-year-old has been in the Fassa Bortolo team since 2003. He won the Paris-Nice in 2001 and the Tour of Romandie in 2001 and 2002. He was also Italian time trial champion and took the Zurich championship in 2002.
The other members of Fassa Bortolo were starting Wednesday's 11th stage of the Tour de France between Courchevel and Briancon.
Russia's Evgeni Petrov was expelled from the Tour de France before Tuesday's 10th stage after failing a blood test. He was the first rider barred from this year's race following a blood test.
"We can't imagine that the scourge of cheating is over," said Christian Prudhomme, a tour director. "If it turns out that people who cheat get kicked out, that's what we want with a big kick in the rear."
Associated Press Writer Thierry Boinet contributed to this report.