Bacterial Vaginosis (BV): This is often the most common cause of abnormal vaginal discharge. The discharge is typically white or gray, with a fishy odor, and is associated with an imbalance in the normal vaginal flora.

Yeast Infection (Candidiasis): Characterized by a thick, white, cottage cheese-like discharge, often accompanied by itching and redness of the vulva and vagina.
Trichomoniasis: A sexually transmitted infection that can cause a frothy, yellow-green or gray vaginal discharge with an unpleasant smell.
Vaginal Atrophy: Thinning and drying of the vaginal walls due to decreased estrogen levels, which can lead to a thin, white or yellowish discharge.

Gonorrhea: A sexually transmitted infection that can cause a thick, greenish-yellow discharge. It's crucial to diagnose and treat promptly to prevent complications like pelvic inflammatory disease.
Chlamydia: Another sexually transmitted infection that may cause an abnormal vaginal discharge, though it often presents with minimal symptoms. Early detection and treatment are vital to prevent long-term reproductive health issues.
Cervical Cancer: Though rare, abnormal vaginal discharge can be a symptom of cervical cancer. Regular screening is essential for early detection.

Foreign Body: The presence of a foreign object in the vagina, which can cause a foul-smelling discharge. This is more common in young girls who may insert objects into their vagina out of curiosity.
Desquamative Inflammatory Vaginitis (DIV): A rare condition characterized by a purulent, greenish discharge and significant inflammation of the vaginal walls.
Vaginal Tuberculosis: A rare condition in many parts of the world, which can cause abnormal vaginal discharge among other symptoms like pelvic pain and infertility.