After the leaves of Toona sinensis are aged in autumn, the cellulose becomes hard and aging, which is not easy to digest and contains high nitrate and picroside. The nitrate content of Toona sinensis leaves increased with the growth period, exceeding the safety standard. Toona sinensis leaves are tender leaves of Toona sinensis, a deciduous tree of Meliaceae, also known as Toona sinensis head and Toona sinensis bud, and are tree-borne vegetables listed in early spring.