Green vaginal discharge is almost always a sign of infection. Normal discharge ranges from clear to white or slightly off-white, so a noticeable green or yellow-green color means something is triggering an inflammatory response. The most common causes are sexually transmitted infections like trichomoniasis and gonorrhea, though a forgotten tampon or other retained object can also be responsible.
Trichomoniasis Is the Most Common Cause
Trichomoniasis, caused by a tiny parasite spread through sexual contact, is the infection most closely associated with green discharge. The discharge is often frothy and yellow-green with a fishy smell. You may also notice itching, burning during urination, or general vulvar discomfort. About 70% of people with trichomoniasis have no symptoms at all, so a partner can pass it along without knowing.
During pregnancy, trichomoniasis carries extra risk. A 2021 systematic review found significant links between trichomoniasis in pregnancy and premature rupture of membranes, preterm delivery, and low birth weight. If you’re pregnant and notice green discharge, getting tested quickly matters.
Gonorrhea and Chlamydia
Gonorrhea frequently produces a yellow-green or greenish discharge, sometimes with pelvic pain, bleeding between periods, or burning when you urinate. Chlamydia can cause similar symptoms, though its discharge tends to be more yellowish than distinctly green. Both infections can be present at the same time, and both can exist with very mild symptoms that are easy to dismiss.
Left untreated, either infection can progress to pelvic inflammatory disease (PID), which develops when bacteria spread from the cervix into the uterus or fallopian tubes. Signs of PID include lower abdominal pain, fever, pain during sex, and unusual foul-smelling discharge. PID can cause lasting damage to reproductive organs, including scarring that leads to chronic pain or difficulty getting pregnant.
A Retained Tampon or Foreign Object
A surprisingly common and non-STI cause of green discharge is a forgotten tampon or other object in the vagina. The discharge can be yellow, green, pink, gray, or brown, and it almost always comes with a strong, foul odor that gets worse over days. Tampons should be changed every 4 to 6 hours and never left in for more than 8 hours. If you suspect this is the cause, a healthcare provider can remove the object quickly, and the discharge typically resolves on its own within a day or two once it’s out.
How Green Discharge Differs From BV
Bacterial vaginosis (BV) is the most common vaginal infection overall, but it doesn’t typically cause green discharge. BV produces a thin, white or grayish discharge with a fishy odor. If your discharge is clearly green or yellow-green, especially if it’s frothy or thick, BV is less likely and a sexually transmitted infection is more probable. That said, BV and trichomoniasis can share overlapping symptoms, including the fishy smell, so testing is the only reliable way to tell them apart.
One distinguishing detail: both BV and trichomoniasis raise vaginal pH above its normal level of around 4.5, but trichomoniasis often pushes pH above 6. You won’t be measuring this at home, but it’s one of the tools a provider uses during evaluation.
How Testing Works
If you go in for green discharge, your provider will likely collect a vaginal swab. The most accurate test available uses a molecular method called nucleic acid amplification, which detects the genetic material of the infecting organism. For trichomoniasis, this type of test has a sensitivity and specificity of about 99%, meaning it catches nearly every true case and almost never gives a false positive. It’s a significant improvement over older methods like looking at a swab under a microscope, which misses infections roughly half the time.
Most clinics can also test for gonorrhea and chlamydia from the same swab. Results typically come back within a few days, though some rapid tests give answers within an hour.
What Treatment Looks Like
Trichomoniasis is treated with a course of oral antibiotics, usually taken twice a day for seven days. An alternative is a single, larger one-time dose of a related antibiotic. Treatment is straightforward, and the infection clears in the vast majority of cases. Your sexual partner needs to be treated at the same time, even if they have no symptoms, or they’ll pass the parasite right back to you.
Gonorrhea and chlamydia are also treated with antibiotics, though the specific regimens differ. For both infections, retesting a few months after treatment is recommended because reinfection rates are high.
If your partner can’t or won’t come in for their own appointment, a system called expedited partner therapy allows your provider to write a prescription for your partner without examining them first. This is legal in 48 states and Washington, D.C., and it’s specifically designed for situations involving chlamydia or gonorrhea. Ask your provider about it if getting your partner to a clinic is a barrier.
What to Pay Attention To
Green discharge on its own is reason enough to get tested. But certain accompanying symptoms suggest a more urgent situation. Lower abdominal pain combined with fever and foul-smelling discharge can signal PID, which needs treatment promptly to prevent permanent damage. Pain or bleeding during sex, burning urination, and bleeding between periods are also signs that an infection may be progressing.
Even if the discharge seems mild or comes and goes, the infections that cause it don’t resolve without treatment. Trichomoniasis can persist for months or years if untreated, and untreated gonorrhea or chlamydia can silently damage the reproductive tract long before symptoms become severe.