How long it takes to get better from applying erythromycin ointment to perianal itching in women depends on the cause of the perianal itching and sensitivity to the drug. There are many causes of perianal itching in women, such as bacterial or fungal infections, diseases such as hemorrhoids or anal fistulas, parasites, texture of clothing, irritating foods or allergic substances. Erythromycin ointment belongs to the macrolide class of broad-spectrum antibacterial agents, which can play an antipruritic, antiseptic and anti-inflammatory role in perianal itching caused by a variety of pathogenic bacteria or anorectal diseases. After cleaning the anus, erythromycin ointment can be evenly applied to the perianal area with a thickness of about 1-2mm. If the patient is more sensitive to erythromycin, it can be kept for about 20 minutes to feel relief from the itching around the anus. However, it should be noted that erythromycin ointment has no obvious effect on perianal itching caused by parasites, clothing texture, irritating food or allergic substances, and it is recommended to treat the itching symptomatically from the root cause. Therefore, it is recommended that patients develop good hygiene habits, change underwear regularly, keep the perianal area clean and dry, wash the anus with warm water after stool or before going to bed; and avoid contact with allergenic chemicals and spicy and stimulating foods, eat more vegetables and fruits, and keep a light diet; at the same time, go to the anorectal department of the hospital in time to treat diseases that may cause perianal itching, such as hemorrhoids, eczema, contact dermatitis, etc.