Most of the Chinese medicinal substances are from plants. During different growth phases, the roots, stems, leaves, flowers and fruits differ greatly in the active principle and content, quality, curative effect, toxicity and side effects, so they must be gathered in the optimal time. Take Mori for an example. Its leaves (Folium Mori) must be gathered after the Frost Descent in late October; its twigs (Ramulus Mori) must be gathered in late spring and early summer; its fruits (Fructus Mori) must be gathered between July and June when they are in violet red.Herba Artemisiae Scopariae gathered in March can be used as an herbal medicine; when they are gathered in May, they would be only firewood.
Herbs: Most are gathered when they are exuberant in early blossom. For some herbs like Herba Artemisiae Scopariae, its seedling is gathered.
Leaves: Most are gathered when they are green before blossom or maturity. But Folium Mori is gathered after Frost Descent in autumn.
Flowers: Most are gathered when buds are just ready to bloom, e.g. Flos Magnoliae, Flos Sophorae, and Flos Caryophylli. Some are gathered when they are in full blossom, e.g. Flos Chrysanthemi and Crocus sativus .
Fruits and seeds: Most of the fruits are gathered when they are ripe or almost ripe. Seeds are gathered when the fruits are ripe.
When the content of the active principle is highest, it is the time to collect.