Ballota nigra (black horehound) is a perennial herb of the family Lamiaceae. It is native to the Mediterranean region and to central Asia, and it can be found throughout Europe. It is also naturalized in Argentina, New Zealand, and the Eastern United States. It blooms in the Northern Hemisphere from May to August.
The whole plant is as offensive in odour as it is unattractive in appearance. It is a common wayside perennial, has stout-branched stems, egg shaped wrinkled leaves, and whorls of numerous dull purple flowers.