The water used must be pure and clean except some special need. Tap water, well water or distilled water can be used. Our forefathers used to take running water, spring water, wild cabbage-washing water and rice-washing water. Sometimes it is necessary to use liquor or watery wine according to the characteristic of drugs as well as the illness condition. The amount of water used depends on the amount and quality of drugs and time needed. As prepared herbal pieces are dry and able to absorb large amount of water once put in it, adequate amount of water must be put in the pot for boiling drugs. Usually a dose of drugs is decocted twice, some three times. For the first decocting, water is added until the drugs are 3 -5cm underwater, and less water may be used for the second and third decocting, each with 100 - 200 ml decoction.