紫苏（学名：Perilla frutescens），古名荏、䖆，又名苏、白苏、桂荏（《尔雅》）、荏子、赤苏、红苏、香苏、黑苏、白紫苏、青苏、野苏、苏麻、苏草、唐紫苏、皱叶苏、鸡苏、臭苏、大紫苏、假紫苏、水升麻、野藿麻、聋耳麻、孜珠、兴帕夏噶（藏语）等，是唇形科紫苏属下唯一种，一年生草本植物，主产于东南亚、**、中国大陆江西、湖南等中南部地区、喜马拉雅地区，日本、缅甸、朝鲜半岛、印度、尼泊尔也引进此种，而北美洲也有生长。

在中医中，紫苏的茎、叶和种子均可入药，其叶称为苏叶，具有解表散寒、行气和胃功效；其果实紫苏子又名苏子、黑苏子、野麻子、铁苏子，具有降气消痰、平喘、润肠功效；紫苏梗有理气宽中、止痛、安胎功效。

Shiso (/ˈʃiːsoʊ/, Japanese:紫蘇 or シソ, [ɕiso̞]) is the more widely used name of the Asian culinary herb Perilla frutescens var. crispa, belonging to the mint family.

This herb was previously known as the "beefsteak plant", a mostly obsolete name. It is also sometimes referred to by its genus name "Perilla", which is ambiguous, as it is also inclusive of the so-called "wild sesame" variety, P. frutescens var. frutescens, which is devoid of the distinctive shiso fragrance.