James Locke, a flight surgeon at NASA's Johnson Space Center in Houston, has made dozens of people sick in the name of science. When he puts subjects in a spinning chair designed to induce motion sickness, roughly 70 percent of them succumb--and at nearly the exact same point on each ride. Locke has used this research and his work with shuttle astronauts to determine which medications and doses best prevent the nausea and vomiting associated with motion sickness.

Unfortunately, while the chair always goes through precisely the same motions, the real world is less predictable. In a ship at sea or on a small plane in turbulence, for example, the type and amount of motion can vary dramatically--and so can its effects on people.

Researchers like Locke, and those who work with pilots and the military's most frequent flyers, are especially keen to find better ways to treat motion sickness. And the many civilians who face nausea in cars, planes, boats or even the tamest amusement park rides would welcome a cure without the common side effects of current medications, such as sleepiness, or the questionable efficacy of alternative treatments, such as pressure bracelets. The path to those ends remains bumpy and filled with more than a few green faces, but new research is closer to finding the best treatments to keep both side effects and lunch down.