Taoist health preservation begins with nourishing the kidney, which governs water. Its color is black, black flax is black, and the best way to tonify kidney is black flax. There are three kinds of flax: black, yellow and white, but only the black flax corresponding to the true color of kidney has medicinal value and health care function. Neither flax nor white flax can be used, only as general food. Our usual diet only stays at the level of "what to eat", only at the primary school level, and the effect is not obvious. So we often have people complain: "I heard that eating flax can tonify the kidney." I ate a lot, why didn't it work? " In fact, we should really learn to use flax for dietotherapy. Jiuzhi flax pill is a traditional Taoist health food. Sun Simiao Jiuzheng Jiusun Flax Pills Prescription: Proper amount of flax, Jiuzheng Jiusun, grinding; Jujube is pitted and mashed into mud. Flax is twice as big as jujube paste and made into paste or pill. Taking 1 pill every morning and evening has the functions of invigorating spleen and kidney, blackening hair and caring skin. Used for juvenile kidney deficiency and senile gray hair.