The pathogen of this disease is Trichomonas vaginalis. Trichomonas is a parasite but invisible to the naked eye. This Trichomonas is pear-shaped, 10 – 30 μm long and has 4 flagella on its head equal to the body of the worm, which can be clearly seen under a microscope. Trichinella is very adaptable to different environments and can grow and reproduce at 25℃–42℃, survive at a low temperature of 3℃–5℃ for 21 days, and still survive for 20–60 minutes at 46℃, and can survive for several hours in semi-dry conditions after being separated from the human body. Trichomonas parasitizes not only the vagina, which is deprived of oxygen, but also invades the urethra and paraurethral glands, and even travels up to the ureter and renal pelvis. The most suitable pH for Trichomonas growth is 5.5-6. If the pH is below 5 or above 7.5, the growth of Trichomonas will be inhibited. The following issues should be noted when treating genital trichomoniasis: (1) Some people have lost appetite or nausea and vomiting after taking methotrexate, but it is not necessary to stop the medication if the symptoms are mild. (2) Keep the vulva clean during treatment, wash it 1 – 2 times a day and avoid sexual intercourse. Underwear and towels should be disinfected by boiling for at least 15 minutes. (3) Methotrexate taken early in pregnancy has the potential to cause fetal malformations, so it should not be taken in the first 20 weeks of pregnancy and should be treated mainly locally. (4) Trichomonas is mutually transmitted between husband and wife, and the man should be actively examined and treated after the woman is found to be ill. Some people are not sick, but he or she is a healthy carrier and should also receive treatment.