(Business 2.0) - No one likes a hangover -- least of all corporate America. According to the journal Annals of Internal Medicine, sick days after overindulgent nights cost the U.S. economy $148 billion annually. But business is booming for the 50-plus hangover remedies now on the market, more than a quarter of which came out during the past two years. That doesn't mean the market is flooded with effective cures: Congress ruled in 1994 that manufacturers don't have to prove that products work as long as they're safe. "Consumers are skeptical," says Lynn Dornblaser, director of consulting at research firm Mintel International. "It's a stretch to think that a pill cures all those symptoms."

The best-selling hangover fighter, Living Essentials's Chaser, has some scientific backing. A 2002 study found that the pills reduced headaches and light sensitivity using activated charcoal--shown to absorb impurities in many dark alcohols--and in August the National Advertising Division of the Council of Better Business Bureaus ruled that Chaser could make hangover-prevention claims in its ads. Sales at major drugstores and supermarkets shot up 159 percent last year to nearly $7 million, according to Information Resources. Chaser's competitors, meanwhile, are pushing other ingredients. Cheerz claims that its amino acids break down alcohol's toxic by-product, acetaldehyde, while HPF Hangover Prevention Formula relies on an extract of prickly pear cactus skin. Both brands say they're nearing $1 million in annual sales. Sounds like a cause for celebration.