At present, Lamian Noodles in Lanzhou uses the instant plaster developed and produced by Lisi Chemical Plant of Lanzhou University (also called Lanzhou Beef Lamian Noodles Preparation). Clean and sanitary, remove harmful components such as lead, arsenic, cyanide and hydrogen from the ash, which makes people feel more at ease when eating. However, it does not rule out that individual businesses add other additives that are harmful to the human body in order to make profits. So it's better to go to a regular store to eat.