Not necessarily yam or iron bar yam. Authentic yam is yam, which is produced in Huaiqing County, Henan Province. The yam produced in Guangxi is called yam. Vegetable yam is the authentic yam that has been preserved. At present, medicinal yam tastes bad and has high yield. It's not yam anymore. If yam is used as medicine, the cost is higher. Don't be mistaken for poor curative effect by the word "vegetable". There are also yams that can't be used as vegetables, and there are medicines.

Eat yam, don't eat it with wheat flour, the effect is not good. It's in the book.

It is best to have yam with some brown sugar.

If you take it for a long time, you may have bloating. Just add some Chinese medicine poria cocos, which complement each other.