"Cai xin" redirects here. For the Chinese media group, see Caixin.
Choy sum (also spelled choi sum, choi sam in Cantonese; cai xin, caixin in Standard Mandarin) is a leafy vegetable commonly used in Chinese cuisine. It is a member of the genus Brassica of the mustard family, Brassicaceae (Brassica rapa var. parachinensis or Brassica chinensis var. parachinensis). Choy sum is a transliteration of the Cantonese name (Chinese: 菜心), which can be literally translated as "heart of the vegetable". Choy sum is also called yu choy (you cai in Standard Mandarin; Chinese: 油菜). It is also known as Chinese flowering cabbage.[1]