Robin Harford 
If you’ve ever walked past a plant that initially looked like it was a stinging nettle or maybe a dead nettle, and then when you got closer you realised it wasn’t, you may well have met black horehound (Ballota nigra).
When gathered and crushed, it has a scent many find unpleasant, though I consider it musky and slightly warm.
It feels nourishing but, through scent, clearly medicinal rather than culinary.
As a Lamiaceae (mint family) member, it can resemble dead nettle at first glance.
Black horehound has been used across Europe, valued mainly as a nervine, a herb that calms anxious minds and aids sleep. In Italy and Moldova, it is prepared as a simple tea.
Some herbalists note, though, that nervine effects are not always straightforward. While it may aid sleep and regulate nerves, one should consider the underlying causes.
For those considering its use for nerves or sleep, consult a qualified medical herbalist to explore deeper causes, as initial symptoms can be misleading.
In Southern Europe, it is also drunk as a tea for upset stomachs or minor digestive issues.
As a tea, it is also used for stubborn coughs. Fresh, pulped leaves can be applied as a poultice to wounds.
Ethnobotanist Peroni documented its occasional use as a medicinal food in Italian communities, where leaves are occasionaly added to wild greens for blood cleansing.
Tasting the leaf, I noticed a strong yet pleasant bitterness, much like aromatic bitters that prepare the digestive system before meals. Although generally not used as food, some Italian regions do mix it with other greens.
In Spain and Italy, the plant is burned as an insect fumigant. I appreciate its look and its distinctive purple Lamiaceae flowers.