Lithospermum erythrorhizon, the purple gromwell, red-root gromwell, 紫草 zicao (Pinyin: zǐcǎo), 紫草 murasaki･sō (Japanese) is a plant species in the genus Lithospermum. The dried root of Lithospermum erythrorhizon (lithospermum root or Lithospermi Radix, Kanji: 紫根, Katakana: シコン, Pinyin: zǐ gēn, Traditional Chinese: 紫根, Simplified Chinese: 紫根) is a Chinese herbal medicine with various antiviral and biological activities, including inhibition of human immunodeficiency virus type 1 (HIV-1).