Green discharge is almost always a sign of infection. Normal vaginal or penile discharge ranges from clear to white, sometimes with a slight yellow tint. When discharge turns green, it typically means your body is fighting off bacteria or a parasite, and the most common culprit is trichomoniasis, a sexually transmitted infection caused by a microscopic parasite.
Trichomoniasis: The Most Common Cause
Trichomoniasis is the most treatable and widespread non-viral sexually transmitted infection worldwide, and green or yellow-green discharge is one of its hallmark symptoms. The discharge is often frothy or bubbly in texture and carries a noticeable fishy smell. The parasite disrupts the natural acid balance of the vagina, pushing the pH from its normal range (around 3.8 to 4.5) up to 5.4 or even 6.5 and above. That shift in pH allows harmful bacteria to flourish alongside the parasite, which is what produces the change in color and odor.
Not everyone with trichomoniasis develops obvious symptoms. Some people carry the infection for months without realizing it. When symptoms do appear, they can include itching, burning during urination, and soreness around the genitals in addition to the green discharge. In men, the infection can cause a yellow or green discharge from the penis, irritation inside the penis, or a burning sensation after urination or ejaculation. Men are less likely to have noticeable symptoms than women, which makes it easy to pass the infection back and forth between partners without knowing.
Other Infections That Cause Green Discharge
Gonorrhea is another STI that can produce discharge in the yellow-to-green range. It tends to cause thicker, more pus-like discharge compared to the frothy consistency of trichomoniasis. Gonorrhea can infect the vagina, penis, throat, or rectum, and many people, particularly women, have no symptoms at all. When symptoms do show up, they often include painful urination and increased discharge that looks different from your normal.
Chlamydia less commonly causes green discharge, but it can produce unusual yellow discharge. Like gonorrhea, chlamydia frequently causes no symptoms, which is why routine screening matters if you’re sexually active with new or multiple partners.
Bacterial vaginosis (BV) is a non-sexually-transmitted condition where the balance of bacteria in the vagina shifts. BV more commonly causes grayish-white discharge with a fishy odor, but in some cases the discharge can take on a greenish tint, especially if a secondary infection develops alongside it.
How Green Discharge Is Diagnosed
Testing is straightforward. A healthcare provider can collect a swab from the vagina, penis, or cervix, or simply ask for a urine sample. For trichomoniasis, some clinics can examine the swab immediately under a microscope and spot the parasite on the spot. Other clinics send the sample to a lab for more advanced testing. The microscope method (called a wet mount) catches the infection about 50 to 80 percent of the time, while newer lab-based tests using DNA amplification are significantly more accurate. Swabs taken from the vagina tend to give more reliable results than those from the penis or urine samples.
Because multiple infections can cause similar symptoms, your provider will likely test for gonorrhea and chlamydia at the same time. These tests use the same type of swab or urine sample, so there’s no extra discomfort involved.
What Treatment Looks Like
Trichomoniasis is treated with a course of oral antibiotics. Women typically take the medication twice daily for seven days, while men often receive a single, larger dose. An alternative medication is available if the standard one causes side effects. Both options are prescription-only and highly effective. Your sexual partner needs to be treated at the same time, even if they have no symptoms, or the infection will simply bounce back.
Gonorrhea and chlamydia are also curable with antibiotics, though they require different medications. Getting tested is the only way to know which infection you’re dealing with and which treatment will work.
You should avoid alcohol during treatment for trichomoniasis, as the medication can cause nausea and vomiting when combined with alcohol. Most people notice the discharge clearing up within a week of starting treatment.
Why Ignoring It Is Risky
Untreated infections that cause green discharge can lead to pelvic inflammatory disease (PID), a condition where bacteria travel upward from the vagina into the uterus, fallopian tubes, and ovaries. PID symptoms include lower abdominal pain, fever, pain during sex, burning when you urinate, bleeding between periods, and unusual discharge with a bad odor. Left untreated, PID can cause long-term pelvic pain and fertility problems.
During pregnancy, the stakes are higher. Untreated trichomoniasis increases the chances of preterm delivery and low birth weight, both of which can affect a baby’s development and lead to extended hospital stays after birth. In rare cases, the infection can pass to the baby during vaginal delivery, though this is uncommon and treatable with antibiotics. Untreated trichomoniasis also makes you more susceptible to contracting or transmitting HIV.
What Makes Green Discharge Worse
Douching is one of the worst things you can do when you notice unusual discharge. It disrupts the natural bacterial balance of the vagina and can push infection-causing bacteria deeper into the reproductive tract, potentially triggering PID. Douching also masks symptoms temporarily, making it harder for a provider to diagnose the problem accurately. If you’re planning to get checked, avoid douching beforehand.
Scented soaps, sprays, and wipes applied to the genital area can also irritate already-inflamed tissue and throw off your vaginal pH further. Warm water and unscented soap on the external area is all you need for daily hygiene. The vagina cleans itself internally through its own discharge, and interfering with that process creates the conditions infections thrive in.
Green Discharge vs. Normal Discharge
Normal discharge changes throughout the menstrual cycle. It can be thin and slippery around ovulation, thicker and white in the days before a period, or barely noticeable at other times. A slight yellow tint on underwear after discharge dries is also normal, since discharge oxidizes when exposed to air.
Green discharge is different. It’s accompanied by at least one other signal: a strong or fishy odor, itching, burning, pain during sex, or a frothy or unusually thick texture. If your discharge has genuinely changed to green and comes with any of these symptoms, that’s your body telling you an infection is present and needs treatment. The good news is that the most common causes are entirely curable, often within a single week.