Trichomoniasis, sometimes called “trich,” is a sexually transmitted infection. It’s common, but it’s easily treatable.

Trichomoniasis is a common sexually transmitted infection (STI). According to the Centers for Disease Control and Prevention (CDC), 3.7 million Americans are living with trichomoniasis at any given time.

Trich is easily treated.

Trich often has no symptoms. The CDC reports that only 30 percent of people who have acquired trich report any symptoms at all. In one study, 85 percent of affected women didn’t have any symptoms.

When symptoms do occur, they often begin 5 to 28 days after a person gets the condition. For some people, it can take much longer.

The most common symptoms among people with vaginas are:

The most common symptoms in people with penises are:

Trich is caused by a one-celled protozoan organism called Trichomonas vaginalis. It travels from person to person through genital contact during sex or from shared sex toys.

In women and those with vaginas, the organism causes an infection in the vagina, urethra, or both. In men or people with penises, the infection only happens in the urethra.

Once it begins, it can easily be transmitted through genital contact without a condom or other barrier method.

Trich isn’t transmitted through normal physical contact such as hugging, kissing, sharing dishes, or sitting on a toilet seat. In addition, it can’t be spread through sexual contact that doesn’t involve the genitals.

One million new cases of trich are estimated each year, according to the American Sexual Health Association (ASHA) and the CDC.

Trichomoniasis is more common in women than in men, and 2.3 million women who acquire it are between the ages of 14 and 49.

It’s more common among older people and especially in those with vaginas. One study showed that the most positive cases occurred in the over 50 age group.

The risk of transmission can increase due to having:

  • multiple sexual partners
  • a history of other STIs
  • previous trich transmissions
  • sex without a condom or other barrier method

Trich symptoms are similar to those of other STIs. It can’t be diagnosed by symptoms alone. Anyone who thinks they may have acquired trich should see a doctor for a physical exam and laboratory tests.

A number of tests can diagnose trich, including:

  • cell cultures
  • antigen tests (antibodies bind if the Trichomonas parasite is present, which causes a color change)
  • tests that look for Trichomonas DNA
  • examination of samples of vaginal fluid, urethral discharge, or urine under a microscope

Trichomoniasis can be cured with antibiotics. Your doctor may recommend metronidazole (Flagyl) or tinidazole (Tindamax).

Don’t drink any alcohol for the first 24 hours after taking metronidazole or the first 72 hours after taking tinidazole. It can cause severe nausea and vomiting.

Make sure your sexual partners are tested and take the medication, too. Not having any symptoms doesn’t mean they haven’t acquired it. You will need to avoid sexual contact for a week after you and all partners have been treated.

Without treatment, trich can be ongoing. With treatment, it’s usually cured within a week.

You can contract trich again after treatment if your partner wasn’t treated or if a new partner has contracted it.

Reduce your chances of acquiring trich again by making sure all of your sexual partners get treatment. Then, wait for the condition to clear before becoming sexually active again. It’s recommended that you wait 1 week after taking your medication before having sex again.

Your symptoms should go away after a week. If your symptoms continue longer, talk to your doctor about getting retested and retreated.

See your doctor for a follow-up test for trich at least 3 months after your treatment. The re-acquisition rate for women and those with vaginas can be as high as 17 percent in the 3 months after treatment.

Re-acquisition is possible even if your partners were treated as well. There are cases of trich being resistant to certain medications.

Some tests can be conducted as soon as 2 weeks after your treatment. Because of a lack of data supporting rescreening for men and people with penises, they’re generally not retested.

A trich transmission can make it easier to contract other STIs. Genital inflammation caused by trichomoniasis can increase your risk of getting HIV, along with other STIs. It also becomes easier for you to transmit HIV to someone else when you have trich.

Other conditions such as gonorrhea, chlamydia, and bacterial vaginosis often occur along with trich. Untreated conditions can result in pelvic inflammatory disease (PID). Complications of PID include:

  • fallopian tube blockage due to scar tissue
  • infertility
  • chronic abdominal or pelvic pain

Trich can cause unique complications in those who are pregnant. There can be a higher chance of delivering prematurely or delivering a baby with low birth weight.

Although rare, transmission to the baby during delivery can occur.

It’s safe to take the medications metronidazole and tinidazole during pregnancy. No adverse effects have been noted.

If you’re pregnant and suspect that you’ve acquired trich or any other STI, talk to your doctor as soon as possible to prevent complications for you and your child.

You can only fully prevent acquiring trich by abstaining from all sexual activity.

Use latex condoms or other barrier methods during sexual activity to reduce your chances of acquiring trich and other STIs.


My partner has an STI, but I don’t have any symptoms. Why would I need to get tested or take the same medication?

Anonymous patient


STIs are common conditions among sexually active individuals. Oftentimes people who have acquired STIs like chlamydia, gonorrhea, and trich don’t have any symptoms. It’s not uncommon for people to find out that they have it only after they’ve been tested. When a sexual partner is diagnosed with an STI, the CDC recommends that all partners be treated while waiting for test results on themselves. This lowers the chance of complications.

For people with vaginas, getting an STI is more complicated than it is for others. Because the vagina connects to the cervix, the opening to the uterus, this makes it easier for conditions that start in the vagina to move up into the uterus, fallopian tubes, and abdominal cavity. This causes the serious condition PID.

For people with penises, delaying diagnosis and treatment means they risk developing more difficult-to-treat conditions and may unknowingly pass it on to other people.

The best way to prevent complications of STIs is to check for and treat them before they become more serious.

Judith Marcin, MDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
Was this helpful?