A gel is a semi-solid substance, made from a polymer solution or sol under certain specific conditions, characterized by increased viscosity and enhanced elasticity. Gels can constitute many drugs or chemicals used in life and medicine to treat diseases and aid in examinations. Commonly used in ultrasound examination, such as medical coupling agent, is a gel, this gel coated in front of the ultrasound probe, can eliminate the air between the skin of the examination area and the ultrasound probe, making the ultrasound image more clear, improve the efficiency and accuracy of the examination. Again, gynecological vaginal drugs are often gel preparations, such as ginseng gel, recombinant human interferon gel, pao gynecological gel, etc., which has a lubricating effect, which can reduce the resistance of the drug into the vagina, expanding its therapeutic area inside the vagina to facilitate the operation.