The first generation of hot compress sea salt and the second generation of hot compress sea salt: In order to extend the use time, Taiwan's Budai salt field came out in 1998 after 4 years of long-term research. Because it can be used for 10 to 15 days, it applied for a patent. Even the big green salt sold in pharmacies is also called rock salt, and of course it has many other names. The price in pharmacies is 10 yuan per pound. The disadvantage is that you still need to add Sichuan peppercorns to promote absorption through the meridians. The third generation of hot compress sea salt: it came out in 2004. It has the characteristics of high temperature and non-melting, and the effective minerals are evenly distributed. The use time of special sea salt for pan frying is extended to one month, and the use time of special sea salt for microwave ovens can be extended to 4 to 5 years. It later became very popular. The "Ice and Fire Therapy Pillow" all belong to this type. The advantage is that the gynecological treatment time is shortened to 2 years compared with the second generation sea salt. The previous sea salt required about 3 years. The fourth generation hot compress sea salt is 30 times more effective than the third generation sea salt. It can be used repeatedly for 4 years, shortening the time for treating gynecological diseases and other diseases. It has the advantages of uniform drug release, non-melting at high temperatures, and high mineral enrichment. The disadvantage is that it can only be heated in a microwave. The variety is relatively wide.