Lasix: Drug of Choice, Drug of Champions?

Servis, according to his assistant, only gives young horses Lasix if they bleed, while also spacing out the races of all his runners to give them time to recover.

"Lasix has a tendency to take the edge off a horse," Donnelly said. "It does drain them to an extent."

After the Derby, Servis proceeded with caution before committing Smarty Jones to a run in the Preakness. Normally, he would never run a horse back in two weeks off such a demanding performance. Smarty Jones, however, came out of Kentucky in fine shape.

Horseplayers know it is often wise to bet on a horse receiving Lasix for the first time, but even better the second.

"A lot of people focus on first dope," said Bob Fornoff, a regular horseplayer from Baltimore, "but [some believe] that horses are a little confused the first time."

Miettinis supports this theory.

"[Lasix] helps horses regain the level of ability they may have had had they not bled," the vet said. "Horses that have been bleeding without detection, they use Lasix the first time and expect to still bleed. And they gallop out and see that they haven't. The next time they run, they're not worrying about it. Horses are creatures of habit."

Servis said Smarty Jones bled slightly after the Kentucky Derby -- "nothing to get excited about." In his second run on Lasix, the horse won the Preakness by 11½ lengths, the widest margin of victory in the history of the race.

A study of the race records of 22,589 thoroughbreds conducted in 1999 at Ohio State University found 74 percent of them were likely to be running on Lasix. The study found horses were 1.4 times more likely to win than horses running without the drug.

With his imposing, undefeated record and proven ability to win with or without Lasix, Smarty Jones would be an overwhelming favorite in the Belmont on or off the drug.

"This horse, Smarty Jones, he's the real deal," Miettinis said.

Only Lion Heart, second in the Derby and fourth in the Preakness, raced in the Triple Crown this year without Lasix.

"I did not consider Lasix," Lion Heart's trainer Patrick Biancone said before the Preakness. "If I have a headache, I take aspirin. If I don't have a headache, I don't take aspirin."