Periwinkle offers a lovely little flower, but it is the leaves and the seeds that are used in folk medicine. The leaves and seeds are rich in the chemical vincamine, an alkaloid that has positive effects on memory and has long been used to combat the effects of aging. In the body, it metabolizes into the brain chemical, vinpocetine.
Lesser Periwinkle or common periwinkle (vinca minor) is most often the species within the periwinkle family that is used for natural medicinal purposes. It is known as an astringent agent and as good for controlling excessive blood flow. In that last roll, it is used to treat wounds and to reduce menstrual flow.
Diabetes: However, periwinkle is best known as a natural remedy to help those with diabetes. Periwinkle is said to control swings in blood sugar. There is only limited data to support to this contention, though it has a long history of use behind it for that purpose as an herbal remedy.
Periwinkle is often and most safely taken as a tea.