It may be normal for the leukorrhea to smell slightly sour. This is because the vagina contains a large number of lactobacilli, which are acidic, and most of them are normal if there are no other abnormalities. If a woman’s leukorrhea smells sour and is accompanied by itchy vulva, a high volume of leukorrhea or a severe sour smell of leukorrhea, it may be caused by an inflammatory infection. It may be caused by an inflammatory infection, usually due to a vaginal or cervical infection with microorganisms, and requires a routine white belt test to confirm the type of infection. If it is caused by bacterial infection, vaginal treatment with metronidazole is required. If it is caused by mycosis fungoides, it can be treated with mycoplasma suppositories. If the infection is caused by trichomonas, it can be treated with metronidazole vaginal tablets.