Proanthocyanidins, a class of polyphenolic compounds found in foods like grape seeds, pine bark, and certain berries, have been investigated for their vascular-protective properties. Several studies—primarily small clinical trials and observational studies—have explored their efficacy in managing symptoms associated with chronic venous insufficiency and hemorrhoids. The rationale is based on their antioxidant activity, ability to strengthen capillary walls, and reduce vascular permeability and inflammation.

Some clinical trials, particularly with standardized extracts such as Vitis vinifera (grape seed extract) and Pinus pinaster (pine bark extract, marketed as Pycnogenol®), have reported a reduction in hemorrhoidal symptoms such as bleeding, pain, and edema. For example, a few randomized controlled trials have shown that patients taking proanthocyanidin-rich extracts experienced faster symptom relief when compared to placebo or standard care. The proposed mechanism involves improvement of venous tone and reduction of capillary fragility.

However, the overall quality of evidence is limited by small sample sizes, short durations, and potential conflicts of interest in some studies. Systematic reviews typically rate the evidence as low to moderate quality, and major clinical guidelines do not currently recommend proanthocyanidins as first-line therapy for hemorrhoids.

In summary, there is some scientific evidence suggesting a possible benefit of proanthocyanidins for hemorrhoidal symptoms, but the evidence is not robust, and further large-scale, independent studies are needed.