People who started taking ginger capsules several days before a chemo infusion had fewer and less severe bouts of nausea afterward than others who were given dummy capsules, the federally funded study found.
"We were slightly beside ourselves" to see how much it helped, said study leader Julie Ryan of the University of Rochester in New York.
Results were released Thursday by the American Society of Clinical Oncology and will be presented at the group's annual meeting later this month.
But don't reach for the ginger ale. Many sodas and cookies contain only flavoring - not real ginger, Ryan said. Her study tested a drug-like ginger root extract, and it's not known if people could get the same benefits from ginger teas or the powdered ginger sold as a spice.
Still, ginger capsules may offer a cheap, simple way to fight nausea, which is far more than just a quality-of-life issue, doctors say. Some cancer patients cut treatment short or refuse chemo altogether because of nausea, hurting their chances of beating the disease.
Medicines do a good job of curbing vomiting, but nearly three-fourths of chemo patients still suffer nausea, which can sometimes be worse, Ryan said.
"Patients ask all the time, 'What else can I do?"' said Dr. Richard Schilsky, a cancer specialist at the University of Chicago and president of the oncology society.
Ginger has long been touted for stomach upsets, ranging from motion sickness to morning sickness during pregnancy. Studies have had mixed results.
The new one used a specially formulated gelcap containing concentrated, purified ginger root extract made by Aphios Corp. of Woburn, Mass.
The study involved 644 patients from cancer centers around the nation who had suffered nausea in a previous round of chemotherapy. Two-thirds had breast cancer and the rest, other forms of the disease. They were placed in four groups and given one of three doses of ginger (the equivalent of one-half, 1 or 1½ grams of ginger per day) or dummy capsules in addition to standard anti-sickness medicines.
Patients took the capsules for six days, beginning three days before chemo treatment. They rated their nausea symptoms on a seven-point scale on the first day of each of three treatments.
All of the ginger doses significantly reduced nausea, and the middle and lowest doses gave the best results. Patients taking ginger scored their nausea an average of two or more points lower on the nausea scale, about a 40 percent improvement over their previous chemo treatments without ginger, Ryan said. Those given dummy pills reported hardly any difference.
Timing may have been key to success: An earlier study found ginger did no good when patients waited until the day of treatment to start taking it. In the new study, researchers wanted to see if having ginger in the system ahead of time would help.
"It was just a different way of thinking to treat nausea, to try and pre-empt it," Ryan said.
Ginger caused no side effects in the new study, but doctors say people should talk with their doctors before trying it because it can interfere with blood clotting, especially during cancer treatment or if taken with the blood thinner Coumadin or other commonly used medicines. It's also a risk for people having surgery, the American Cancer Society warns.
The National Cancer Institute paid for the study, and researchers had no ties to the ginger capsules' maker, Aphios. The company already sells a different type of ginger capsule as a dietary supplement, but hopes to seek federal Food and Drug Administration approval to sell its new ginger formulation as a drug to treat nausea, said chief executive officer Trevor Castor.
As dietary supplements, 50 to 100 ginger capsules sell for $6 to $30, Ryan said.
"We can't specifically say if any other form besides the form in our study would work," she added.
Still, it is heartening that ginger may offer hope as a cheap and simple way to ease the burden of chemotherapy on patients and their families, said Dr. Durado Brooks of the Cancer Society.
"It's difficult to watch someone suffer, to watch someone be miserable. So anything we can do to help alleviate chemotherapy symptoms is very welcome," he said.