Ginseng seems to diminish blood thinners' effectiveness.

* THE QUESTION Drugs known as anticoagulants keep blood clots from forming and possibly causing a heart attack or stroke. However, some medications, foods and herbs interfere with these blood thinners. Is ginseng one of them?

* THIS STUDY gave five milligrams of the anticoagulant warfarin (Coumadin) to 20 healthy adults for three consecutive days and then randomly assigned them a week later to take either 1 gram of ground American ginseng root or a placebo daily for the next two weeks. Everyone took warfarin the fourth week, again for three consecutive days. At the end of the study, blood samples revealed lower levels of warfarin in the blood of those who had taken ginseng, compared with those who took the placebo. A test that measures the clotting ability of blood showed a reduction in this ability in the ginseng group.

* WHO MAY BE AFFECTED BY THESE FINDINGS? Anyone who takes a blood thinner, often prescribed for people who have had a heart attack or are at particularly high risk for one.

* CAVEATS The ginseng dose was at the high end of the recommended range; whether smaller doses of ginseng or larger doses of warfarin might alter the findings is unknown. Study participants were generally younger than most people who take warfarin, and they did not have medical conditions that necessitated anticoagulant use; each was paid $250 for participating. The study indicates that ginseng may interact with other medications.

* BOTTOM LINE People taking anticoagulants should remember that ginseng can interfere with the effect of blood thinners, and they should tell their doctor that they take the herb.

* FIND THIS STUDY July 6 issue of Annals of Internal Medicine; abstract available online at

* LEARN MORE ABOUT blood clots at (search for "anticoagulant") and at (click on "Patient Update" and scroll down to patient page on "Treatment of Blood Clots"). Learn about ginseng at (search for "ginseng").

kidney cancer

Nonsurgical treatment appears successful for smaller tumors.

* THE QUESTION For decades, the standard treatment for kidney cancer has been removal of the kidney. A newer technique called radiofrequency ablation uses electrical currents to disintegrate the cancerous tumor, sparing the kidney. How effective is this approach?

* THIS STUDY reviewed the medical records of 22 people whose kidney tumors were treated with radiofrequency ablation at one facility. CT and MRI scans showed that 100 percent of the smaller tumors (less than three centimeters) and 69 percent of the larger ones were eliminated. Patients reported minimal complications (mild pain, for example), and most were hospitalized for less than 24 hours. An average of seven months later, none of the cancers had recurred.

* WHO MAY BE AFFECTED BY THESE FINDINGS? Anyone with kidney cancer, which strikes about 20,000 men and 12,000 women -- most of them over 40 -- each year in the United States.

* CAVEATS The study was not randomized, so there is no direct comparison between this technique and other procedures. Findings relied on follow-up imaging; whether pathology tests would have yielded different results is unclear.

* BOTTOM LINE People diagnosed with kidney cancer may want to ask their doctors about radiofrequency ablation.

* FIND THIS STUDY July issue of the American Journal of Roentgenology; abstract available online at

* LEARN MORE ABOUT kidney cancer at and


Simple exercises may relieve recurrent, short-term dizziness.

* THE QUESTION People who feel five- to 30-second bouts of vertigo when they quickly move their heads generally can get relief through medication or exercises performed under a doctor's or therapist's guidance. Symptoms frequently recur, however. Does self-treatment work?

* THIS STUDY randomly assigned 70 adults who had experienced benign paroxysmal positional vertigo for an average of eight weeks to perform one of two routines three times a day until the dizziness episodes had not occurred for 24 hours. Both routines -- known as a modified Epley procedure and a modified Semont maneuver -- involved specific head and body position changes done while sitting on a bed. The goal was to clear from the inner ear canal loose particles that are believed to cause this type of vertigo. After a week of doing the movements at their homes, 95 percent of the people practicing the Epley routine and 58 percent of those trying the Semont maneuver reported being free of vertigo.

* WHO MAY BE AFFECTED BY THESE FINDINGS? Anyone with positional vertigo, which occurs mainly in people over age 50 and in women more than men.

* CAVEATS Movements must be performed precisely; the lesser success of the Semont maneuver was attributed to incorrect execution by participants. The study did not include a control group to compare the effect of these movements with no treatment.

* BOTTOM LINE People with short-lasting vertigo may want to ask a neurologist about these movements.

* FIND THIS STUDY July 13 issue of Neurology; abstract available online at

* LEARN MORE ABOUT positional vertigo at (under "QuickFind," click "Balance topics," then "BPPV"). To view a video of the movements, go to

-- Linda Searing