The epididymis is located in the posterior lateral part of the testis in the coiled tubule, which is connected to the testis through the testicular output tubule above the testis and hangs together with the testis at the lower end of the spermatic cord. The size of the epididymis is about 6×0.5 cm, while the total length of the epididymal duct reaches 400-600 cm and the diameter of the epididymal duct is 0.4-0.5 mm. The upper end of the epididymis is enlarged and bluntly rounded, called the head of the epididymis, which is attached to the upper end of the testis; the body of the epididymis is slender and vertical, and the lower end becomes the tail of the epididymis, which folds back and extends upward to become the vas deferens. The epididymis is the organ that stores sperm and further matures them. Sperm are stored in the epididymis after the formation of the testes and take about 20 days to further develop and mature before they have the ability to be fertilized, and sperm taken directly from the testes do not have the ability to be fertilized. Many substances secreted by the epithelium of the epididymal duct, such as choline glycolate, carnitine, glycoproteins, various enzymes and a few androgens, are related to the metabolism and maturation of sperm and the maintenance of their normal physiological functions, in addition to supplying them with nutrients and enhancing their vitality. The fluid in the epididymis is acidic, with high osmotic pressure (300-400 mOs), low oxygen content and high potassium ions, which is conducive to the resting state of sperm, and sperm can survive in it for 4 weeks or even longer. The epithelium of the epididymis has a strong absorption function, and 99% of the testicular reticulum secreted by the supporting cells in the testis is absorbed by the epididymis. Phagocytes in the epididymis degrade and absorb sperm that are not expelled in time. Epididymitis is often the twin of prostatitis, and many patients with prostatitis will develop epididymitis, and urethritis can easily cause inflammation of the epididymis. In acute epididymitis, the epididymis will increase sharply and swell within a few hours, and in serious cases, the testicles will become inflamed at the same time, as big as a fist, with unbearable pain and difficulty in walking. Chronic epididymitis is often caused by urethritis or chronic prostatitis, or caused by the extension of acute epididymitis, and patients have recurrent episodes of pain in the epididymis. Exertion, alcohol, stimulating diet and sexual excitement can aggravate the symptoms of epididymitis. Because the function of epididymis is closely related to fertility, pain in the area of epididymis should be seen by a doctor in time. According to our experience taking Chinese herbal medicine Chai-Orange Tang (containing Chai Hu, Orange Kernel, Citrus Aurantium, Licorice, etc.) can quickly relieve the symptoms of pain and swelling. Those who have microbial infections such as bacteria or mycoplasma can combine with antibiotic treatment, and those who have urethritis and chronic prostatitis should actively treat these related diseases simultaneously. Patients who have not had children with epididymitis should have their sperm quality checked so that timely and targeted treatment can be given to improve sperm quality and restore reproductive function.