In analyzing Saturday's $200,000-added Belmont Stakes, the most important factor is the prohibition of the drugs Butazolidin and Lasix. New York does not allow the use of any drugs or medication on race horses.

There is a presumption that all horses in the field who have raced in Florida, California and Kentucky were treated with those two medications. Certainly Codex used them when he invaded Maryland. Rumbo, Rockhill Native and Super Moment probably had been treated. But some areas of the country do not publish that important information.

Why is the drug factor so important?

On May 30, Veiled Look ran out of the money at Bowie as a prohibitive favorite. She again had no Bute in her system. Bute had been outlawed in Maryland since her winning race at Pimlico.

That one dramatic example illustrates the fact that drugs may be the deciding factor in today's Belmont.

Codex, the overnight favorite, has shown dramatic improvement since trainer Wayne Lukas lightened up on his training. The son of Arts and Letters has now won four straight. What effect the withdrawal of Bute will have on him is unknown. With it, he would appear a standout. Without it he appears to be "iffy."

Rumbo, a hard-running second in the 1 1/4 mile Kentucky Derby, has raced mostly in California where drugs are legal, but that information is not made available to the public. If Rumbo wins the Belmont, we may learn after the race that he never raced with drugs. And since Codex has beaten him twice, we can infer that drugs played a part in the outcome.

The same could be said of Super Moment and Rockhill Native, two of the legitimate challengers.

Super Moment has only raced in California and Kentucky where drugs are also legal. The stretch-running son of Big Spruce acts like a 1 1/2-mile horse. But he probably has been racing with medication. Can he negotiate that distance without drugs?

Rochill Native is another contender who has raced where drugs are allowed. Despite a sharp workout, presumably accomplished without medication, he may deteriorate in the stretch, as he did in Kentucky.

Comptroller has won three of five starts and is trained by Angel Penna. However, the son of Reviewer has never been around two turns and would seem to be at a distinct disadvantage insofar as condition is concerned.

The rest of the field appears weak, although Temperence Hill is coming off a decent race on the turf, a positive sign.

Who will win?

I'll wager a deuce on the filly, who appeared to be the victim of the most spectacular daylight purse-snatching in the history of American racing at Pimlico last month.