As the saying goes, "if you have a disease for seven years, you must ask for three years of AIDS." It shows that some old drugs placed for a long time have a certain special curative effect. The so-called old medicine is the medicine that is used after a long period of storage with a certain method. This is a characteristic of traditional Chinese medicine. Some experienced old Chinese doctors especially like to use old medicine. The commonly used drugs of this kind are tangerine peel, tangerine red, Fructus aurantii, Fructus aurantii, cinnamon and donkey hide gelatin. Because after a long time of storage, part of the gas and taste of these drugs have volatilized, so they become light and pure and thin, and the effect is relatively mild. Using them can avoid excessive gas consumption and Yin injury.

Doctor Wu Yifan's "rambling on old medicine"

        There are many kinds of healthy people, such as donkey hide gelatin, donkey hide gelatin, and so on.

Strictly speaking, donkey hide gelatin has no shelf life. As long as there is no mildew and peculiar smell on the surface, it can be eaten. The older the donkey hide gelatin, the better the effect, and the dryness will be eliminated. It won't get angry after eating. The reason why a shelf-life was marked was that the state later stipulated that all drugs should have a shelf-life limit, so there was a shelf-life of 5 years.

       "Ginseng should be new, donkey hide gelatin should be old". It is generally believed that the newly made donkey hide gelatin has fire gas. After long-term storage and fire digestion, Chen donkey hide gelatin has a more sweet and flat taste, a more mild and lasting tonic effect, better efficacy and more conducive to the digestion and absorption of the human body. This is also the reason why old Chinese doctors favor Chen Ejiao.

       According to the Great Dictionary of traditional Chinese medicine, "after the donkey hide gelatin is melted, it has a delicate fragrance and sesame oil gas. The juice is yellowish white, thick but not greasy, and tastes sweet and slightly salty. If its original block is within 50 or 60 years, it will be green and firm in quality; if it is more than 50 or 60 years, it will turn yellow and crisp in quality, which is better. Taking it for pulmonary tuberculosis, it is unique." Now it is difficult to find Chen donkey hide gelatin, so you can store some high-quality new donkey hide gelatin and put it at home for reuse when it becomes Chen donkey hide gelatin after a few years.

       The old donkey hide gelatin produced by the traditional donkey hide gelatin workshop in Dong'e town during the Xianfeng Period of Shi Tiande Hall (one of the predecessors of Fujiao group) has remained intact after a hundred years, and still has the smell of gum. It now exists in the Chinese donkey hide gelatin museum built by fujiaoji Institute.

Place it in a lime tank or bury it in rice bran for closed storage. Donkey hide gelatin is easy to get damp and moldy if it is not well preserved; Donkey hide gelatin is not resistant to high temperature and will melt in hot weather. According to the ancient storage method, it can be stored in a lime tank or buried in rice bran for closed storage. Lime and chaff absorb moisture and thus play a protective role.

Store in wooden case (box) and put moisture absorbent. Donkey hide gelatin can also be stored in a wooden box (box), with a little right ash or other moisture absorbing agent at the bottom of the box to prevent donkey hide gelatin from cake and mildew flower due to moisture. The uneaten donkey hide gelatin should be wrapped in paper (about 100 ~ 200g small bag). The paper bag shall be lined with a layer of old oil paper, and a piece of old oil paper shall be padded between each layer of glue. If there is no old oil paper, you can replace it with food plastic bags to prevent donkey hide gelatin from adhering to the paper. Be careful not to put too much lime in the box.

Seal and refrigerate. With the improvement of production technology, donkey hide gelatin is not so easy to be damp and soft. Generally, it can be put in the shade. If it is a donkey hide gelatin block that has been unpacked, put the donkey hide gelatin in the edible packaging bag, tie the mouth tightly, and put it into the refrigerator for storage.

If the crushed donkey hide gelatin block, or the raw donkey hide gelatin powder, donkey hide gelatin paste and other nourishing foods after bottle opening, they also need to be sealed and stored in the refrigerator. It should be bottled and sealed and put into the refrigerator freezer. Tonic foods such as donkey hide gelatin paste cooked at home also need to be sealed and stored in the refrigerator.