20 to 30 minutes. Mirabilite (also known as travertine or travertine) is a kind of traditional Chinese medicine. It needs pretreatment in the process of decocting Chinese medicine, which is called first frying. The time of first frying mirabilite is 20 minutes to 30 minutes, which is enough to release some effective components of the medicine, but it still retains certain medicinal properties. The purpose of pretreatment is to remove some harmful substances, increase the efficacy and change the medicinal properties.