Capers (Capparis spinosa) have a long history of use in traditional herbal medicine, particularly in Mediterranean and some Asian cultures. Folk remedies have used capers for various ailments, including supporting vascular health. The connection to capillary health may stem from traditional herbalist concepts that capers "strengthen the blood" or "improve circulation." Capers are known to contain bioactive compounds such as flavonoids, rutin, and quercetin, which are recognized for their antioxidant and potential vascular-protective properties.

Modern scientific studies on capers specifically for capillary health or function are limited. Some research has demonstrated that rutin, a major flavonoid found in capers, can help strengthen capillaries and reduce their fragility, which underpins the rationale for using capers in support of the capillary system. However, these studies have generally focused on isolated rutin rather than capers as a whole food or extract. There is a lack of robust clinical trials directly linking caper consumption to improved capillary health in humans.

In summary, while traditional herbal practices have associated capers with benefits to the vascular and capillary systems, scientific validation remains limited and is largely extrapolated from the presence of certain flavonoids. Thus, the use of capers for capillary support is primarily justified by tradition, with some supporting evidence for individual compounds.