May 14, 2009 -- Moms who give their kids ginger ale to soothe upset tummies may find this as no surprise: Ginger may help relieve the nausea of cancer chemotherapy.

In the largest study to date evaluating the benefits of ginger for patients undergoing chemotherapy, as little as one-quarter of a teaspoon of ginger cut symptoms of nausea by 40%.

By the end of the first day, patients who took the two lower doses of ginger -- which Ryan says contains the equivalent of one-quarter and one-half teaspoon of fresh or dry ginger -- rated their nausea as 1 or 2 points, meaning they had no or very slight nausea.

In contrast, those who took a placebo rated their nausea as 4 to 5 points, meaning they had a lot of nausea.

So will ginger ale or ginger snaps do the trick? “Theoretically, as long as they contain one-quarter to one-half teaspoon of fresh or dry ginger. But if it’s ginger flavoring, that wouldn’t work,” Ryan tells WebMD.

Scientists don’t know why ginger relieves nausea, she says.