The leaves turn yellow and slowly drop from the plant body. The matured fruits, called capsules, are papery and brown in color. They should not be allowed to stay too long in the field because the dry capsules burst and the seeds fall off. The seeds are air-dried thoroughly at room temperature and away from direct sunlight immediately after collecting. They are stored in a dry place in air tight containers.
Seeds properly stored can germinate within one year.
Seeds can be used for drug preparation within five years of storage. Use Tunkin seeds not more than five years old. If irritation occurs, discontinue its use. If skin ailment does not improve by the second or third week of application, discontinue the treatment. Consult a physician.