It is a 5-25 cm tall herb with square stem and opposite, oblong, stalked and slightly branched leaves.
The blue-violet flowers are Lip flowers. They sit close together in an axis-like inflorescence.

Many places on Fanø like to grow in light.

Blooms in July – August.

Has been used as a medicinal plant especially as rinsing water against bacteria eg. as mouthwash.