Bioflavonoids are colorful substances that occur widely in the plant kingdom. Reasonably good, though not indisputable, evidence suggests that the citrus bioflavonoids diosmin and hesperidin (in a special micronized combination preparation) may be helpful for hemorrhoids. 12

For example, a 2-month, double-blind, placebo-controlled trial of 120 individuals with recurrent hemorrhoid flare-ups found that treatment with combined diosmin and hesperidin significantly reduced the frequency and severity of hemorrhoid attacks. 1 Another double-blind, placebo-controlled trial of 100 individuals had positive results with the same bioflavonoids in relieving symptoms once a flare-up of hemorrhoid pain had begun. 2 A 90-day, double-blind trial of 100 individuals with bleeding hemorrhoids also found significant benefits for both treatment of acute attacks and prevention of new ones. 3 Finally, this bioflavonoid combination was found to compare favorably with surgical treatment of hemorrhoids. 4 However, less impressive results were seen in a double-blind, placebo-controlled study, in which all participants were given a fiber laxative with either combined diosmin and hesperidin or placebo. 5

Other sources of bioflavonoids have been studied, as well. For example, in a 4-week, double-blind, placebo-controlled trial of 40 people with hemorrhoids, use of an extract made from the bioflavonoid-rich herb bilberry significantly reduced hemorrhoid symptoms as compared to placebo. 10 In addition, according to some but not all double-blind studies, the semi-synthetic bioflavonoids known as oxerutins may also be helpful for hemorrhoids, including the hemorrhoids that occur during pregnancy. 6,7

Although it is not known precisely how flavonoids work, it is thought that they stabilize the walls of blood vessels, making them less susceptible to injury.

For more information, including dosage and safety issues, see the full articles on Citrus Bioflavonoids , Bilberry , and Oxerutins .