The biological form of Polygala vulgaris is hemicryptophyte scapose,[2] as its overwintering buds are situated just below the soil surface and the floral axis is more or less erect with a few leaves.

The colour of the corolla varies between blue and violet, it can rarely occur in purple forms.

On the lower side of the flower lies the third petal; it too, is joined to the stamen tube, but it is larger, and fringed.

[2][3] Common milkwort grows in meadows, slopes, edges of forests, heaths, sunny woods, dunes and grasslands.

[4] According to Classical and Renaissance writers common milkwort was used medicinally as an infusion to increase the flow of a nursing mother's milk.