Buddhists abstain from eating meat (even eggs) to avoid killing living beings. Monks follow a life-long vegetarian diet (ăn chay trường).
Lay believers observe periodical abstinence (ăn chay kỳ) on designated days of the lunar month. Depending on the individual, this may be two days, i.e. at new and full moons; or four, six, or ten days.
Longer periods include a month’s abstinence (nhất nguyệt trai) during the first or seventh lunar month; three months’ abstinence (tam nguyệt trai), either three consecutive months or three separate months: the first, seventh and ninth or tenth months.