The second method is more mysterious. Sodium, aluminum, sulfur, oxygen and other elements are put into the vessel to avoid sunlight radiation, and the soil blocks sunlight. After hundreds of millions of years, the elements in the soil have mutated many times and completely. Because of the influence of soil, such elements become living things other than animals and plants, with only the breath of life and no life. After swallowing this item, the oxygen inhaled by the body can survive by drinking water. This is an energy conversion.
There is also a kind of Dan medicine that people can't eat directly, but if there is this kind of Dan in a clean lake, there will be some minerals in the water. This kind of Dan is inedible to humans and cannot be moved. It is usually at the bottom of an underground lake.
In addition, the Taoist inner elixir is not an elixir, and it can never be practiced in just a few days. Taoist inner elixir is to turn essence into ammunition, which has the same nourishing effect, but it is obviously not an elixir.