わが国の各地をはじめ、東アジアの温帯地域に広く分布しています。日当たりのよい山野の草地に生え、高さは20〜30センチになります。茎には4稜があり直立し、葉は長楕円状披針形で対生します。6月から8月ごろ、茎の先に肉穂花序をだし、紫色の唇形花を咲かせます。和名は、花序のかたちを矢を入れる靭(うつぼ)に見立てたことから。また、夏に枯れてもそのまま残ることから「かこそう(夏枯草)」とも呼ばれます。台湾華語では「夏枯草」、中国名では「山菠菜(shan bo cai)」。
The Self-heal (Prunella vulgaris ssp. asiatica) belongs to Lamiaceae (the Mint family). It is a perennial herb that is distributed all over Janan, as well as widely in the temperate areas of East Asia. This herb grows in sunny montane grasslands and can reach 20-30 cm in height. The stem is quadrangular and erect. The leaves are oblong-lanceolate and opposite. The spadix is borne on the stem apex and the purple labiate flowers bloom from June to August. The Japanese name "靭草" comes from the shape of the inflorescence, which resembles a quiver of arrows. It is also called "夏枯草" (meaning "summer dead grass") because it withers in summer but remains intact. In Taiwanese, it is called "夏枯草", while its Chinese name is "山菠菜" (shan bo cai).