Metronidazole has a certain therapeutic effect on anal itching caused by inflammatory infections, parasites and other factors, but the therapeutic effect on itching caused by eczema and allergies is not obvious. Metronidazole is a kind of antibacterial drug, has the role of anti-anaerobic bacteria, treatment of parasites, clinically used in the prevention and treatment of bacterial infections, such as proctitis, sinusitis and so on. Therefore, if diagnosed with inflammatory infections and parasitic diseases, the drug can be used under the guidance of a doctor to achieve the therapeutic effect of anti-inflammatory and anti-itching. However, it should be noted that for eczema, allergies and other factors that cause itching discomfort, the application of metronidazole at this time, it is generally difficult to achieve the desired results. It is recommended to choose to use the drug under the guidance of a doctor.