The main reason for the sour smell of the leukorrhea is related to many factors, and there are several possible causes: 1. It is considered a normal physiological phenomenon, because the leukorrhea of women is secreted from the cervix and vagina, which contains a large number of lactobacillus bacteria, and generally there is a sour smell when there is lactobacillus bacteria. 2. It is advisable to go to the hospital for examination and medical treatment.