Green discharge is not normal and almost always signals an infection that needs treatment. The most common cause is trichomoniasis, a sexually transmitted infection that affects roughly 3.7 million people in the United States. Other STIs, bacterial infections, and even a forgotten tampon can also produce green or yellow-green discharge. Unlike a yeast infection, which you can treat with over-the-counter creams, the infections behind green discharge require a prescription.
Trichomoniasis: The Most Common Cause
Trichomoniasis is caused by a tiny parasite called Trichomonas vaginalis, and it’s the single most likely explanation for green vaginal discharge. The discharge is typically thin, may appear clear, yellowish, or greenish, and often has a noticeable fishy smell. It can also come with itching, burning during urination, and general irritation around the vulva.
What makes trichomoniasis tricky is that many people have no symptoms at all. About 70% of infected individuals never notice anything obvious. So if you do have green discharge, the infection may have been present for days or weeks before the color change became apparent. The parasite spreads through sexual contact and can live in the lower genital tract without causing symptoms in the partner who passed it along.
Treatment is straightforward: a course of oral antibiotics, typically taken twice daily for seven days for women or as a single larger dose for men. Both partners need treatment at the same time, even if one has no symptoms, or the infection will bounce back and forth.
Gonorrhea and Chlamydia
Green or yellow-green discharge can also point to gonorrhea or chlamydia, two bacterial STIs that sometimes occur together. Gonorrhea tends to produce thick, cloudy, or bloody discharge along with painful urination and pelvic discomfort. Chlamydia symptoms overlap but are often milder, with burning during urination and lower abdominal pain being the most common complaints.
Both infections frequently produce no obvious symptoms, especially in women. When symptoms do appear, they can take one to three weeks after exposure. Left untreated, either infection can spread deeper into the reproductive tract and cause pelvic inflammatory disease, a serious condition that can lead to chronic pain and fertility problems.
Green Discharge in Men
Men can also experience green or yellow-green discharge from the urethra. The most common cause is urethritis, an inflammation of the tube that carries urine out of the body. Gonorrhea is the leading culprit, but chlamydia, trichomoniasis, and several other organisms can trigger it as well. The discharge may appear on its own or only when the penis is squeezed, and it’s often accompanied by burning during urination and itching at the tip.
Some men notice discharge even without other symptoms, which still warrants testing. A healthcare provider can usually identify the cause with a urine sample or a swab.
Forgotten Tampons and Other Objects
A retained tampon or other foreign object in the vagina can cause discharge that turns yellow, green, pink, or brown, often with an intensely foul smell. This is more common than people realize. The odor is usually the giveaway: it’s strong, unmistakable, and gets worse over time. You may also notice spotting or pelvic discomfort.
If you suspect a retained tampon, try to remove it yourself by bearing down and reaching in with clean fingers. If you can’t reach it or aren’t sure something is there, a healthcare provider can remove it quickly and painlessly. The main risk with a retained object is toxic shock syndrome, which is very rare but serious. Symptoms include sudden high fever, vomiting, diarrhea, and a sunburn-like rash. If those appear, seek emergency care.
Why Over-the-Counter Treatments Won’t Work
It’s tempting to grab a yeast infection kit from the pharmacy, but green discharge is not caused by yeast. Yeast infections produce thick, white, cottage cheese-like discharge that typically has no smell. Green discharge, especially with a fishy or foul odor, points to a bacterial or parasitic infection that requires prescription medication.
Using an OTC antifungal when you actually have trichomoniasis or gonorrhea delays proper treatment and gives the infection more time to spread or cause complications. Even if you’ve had yeast infections before and feel confident recognizing them, a change to green warrants professional testing.
What Testing Looks Like
Getting tested is quick and not particularly uncomfortable. A provider will typically collect a sample of the discharge using a swab. From there, several things can happen: the sample may be examined under a microscope to look for bacteria, white blood cells, or parasites. A “whiff test” checks whether the sample produces a strong fishy odor when mixed with a chemical solution. The acidity of the discharge is measured, since higher-than-normal acidity points toward bacterial causes. In some cases, a PCR test checks the sample for genetic material from specific organisms, though this is less common because of cost.
For STI screening, a urine sample or swab is tested specifically for gonorrhea, chlamydia, and trichomoniasis. Results usually come back within a few days, and treatment can often begin the same day based on the clinical exam.
When Green Discharge Becomes Urgent
Most infections that cause green discharge are easily treatable, but complications can develop if they’re ignored. The biggest concern is pelvic inflammatory disease (PID), which happens when bacteria from the cervix spread into the uterus, fallopian tubes, or ovaries. PID symptoms include lower abdominal pain, fever above 101°F, pain during sex, and irregular bleeding between periods. It can cause scarring that leads to chronic pelvic pain, ectopic pregnancy, or infertility.
If you’re pregnant, green discharge deserves prompt attention. Infections like trichomoniasis during pregnancy have been linked to preterm labor and, in rare cases, infection of the amniotic sac. Detecting and treating the infection early reduces these risks significantly.
What to Expect After Treatment
Once you start antibiotics, symptoms usually improve within a few days. The discharge should return to its normal color and consistency within a week. Avoid alcohol during treatment if you’re prescribed metronidazole or tinidazole, as the combination can cause severe nausea and vomiting. You’ll also need to avoid sexual contact until both you and your partner have completed treatment and symptoms have fully resolved.
Reinfection is common with trichomoniasis and other STIs, so follow-up testing is often recommended about three months after treatment. If your symptoms persist or return after finishing your prescription, go back for retesting rather than assuming the original medication failed.