Trichomoniasis, which most people call “trich” (pronounced as “trick”), is among the most common curable sexually transmitted diseases. Most cases of this infection go unnoticed because most people who are infected aren’t aware of it.

However, it’s estimated that as many as 180 million new trich infections occur globally every year, and, according to the Centers for Disease Control and Prevention, about 3.7 million Americans have trich.

Learn more about this common STD, what symptoms to look out for, how the infection can make a person more susceptible to other STDs and why trich is easy to mistake for other health problems.

In This Section

Trich Symptoms

Fewer than 1 in 3 people who are infected with trich experience any symptoms of the infection. For those whose bodies do show obvious signs of trich, those symptoms generally appear within a week of becoming infected but could take up to a month to show up.

It’s estimated that women are more likely to be infected, and men who have trich are very unlikely to see any obvious physical signs. Common symptoms are similar between men and women, but there are some distinctions.


  • Burning after urination or ejaculation
  • Penile discharge
  • Irritation or itching inside penis


  • Discomfort when urinating
  • Itching, burning, pain or redness of genitals
  • Change in vaginal discharge, including color (clear, white, yellow, green), volume and smell (especially including strong fishy odor)

Trich symptoms can vary from so minor they aren’t noticed to extremely painful and irritating. And because many women who have trich symptoms may mistake the discharge and odor from their vaginas as another STD or even a yeast infection, most trich infections aren’t properly diagnosed.

Trich Transmission

The parasite Trichomonas vaginalis causes trich infections as it’s passed from person to person during intercourse or other sexual activities. The trich parasite is transmitted in bodily fluids like semen, pre-cum and vaginal fluids.

While it’s most often spread during vaginal intercourse, trich also can spread easily by the sharing of sex toys or even through contact with fingers or other body parts that are carrying infected bodily fluids.

For women, the most commonly infected body parts are in the lower genital tract; this includes the vulva, vagina, urethra and cervix. For men, the urethra is the most commonly infected body part.

In addition to spreading via sex toys and vaginal intercourse, it’s also possible to spread trich through vagina-to-vagina contact, and, while it’s considerably less common, trich also can infect the mouth or the anus. Also, sexual intercourse does not have to take place or be finished to completion for trich to be spread from person-to-person.

However, because the parasite lives only in bodily fluids like semen and vaginal fluid, less-intimate contact like kissing cannot cause the STD to be spread from an infected person to another.

Trich Prevalence

About 3.7 million Americans have trich, according to the CDC, but the overall number of new cases varies, and because trich is not a federally notifiable STD like chlamydia or syphilis, it’s difficult to pinpoint exactly how many people have it at any given time.

One method for gauging a relative increase or decline in trich is to examine data on doctor visits. According to CDC data, about 222,000 women between the ages of 15 and 44 sought a doctor’s care for a trich infection in 2016, which represents a huge increase from the 2015 figure of 139,000. However, it’s important to remember that most people who are infected do not get tested, so the number of doctor visits is a mere fraction of the overall prevalence of the infection.

Trich infections by year*

1966 579,000
1967 515,000
1968 463,000
1969 421,000
1970 529,000
1971 484,000
1972 574,000
1973 466,000
1974 427,000
1975 500,000
1976 473,000
1977 324,000
1978 329,000
1979 363,000
1980 358,000
1981 369,000
1982 268,000
1983 424,000
1984 381,000
1985 291,000
1986 338,000
1987 293,000
1988 191,000
1989 165,000
1990 213,000
1991 198,000
1992 182,000
1993 207,000
1994 199,000
1995 141,000
1996 245,000
1997 176,000
1998 164,000
1999 171,000
2000 222,000
2001 210,000
2002 150,000
2003 179,000
2004 221,000
2005 165,000
2006 200,000
2007 205,000
2008 204,000
2009 216,000
2010 149,000
2011 168,000
2012 219,000
2013 225,000
2014 155,000
2015 139,000
2016 222,000

* Initial visits to physicians, women between 15 and 44 only

At-Risk Groups

Any person who has sex or engages in other sexual activity with another person is at risk of contracting and spreading trich, which remains the most common curable STD. However, there are lifestyle and demographic factors that can contribute to a higher risk of becoming infected with trich:

  • Gender: Women are more likely than men to become infected with trich, though people of all genders are at risk.
  • Sexual partners: The more sexual partners a person has, the more statistically likely they are to contract trich.
  • Race: Black women have a statistically elevated rate of trich.
  • Sexual habits: People who rarely use condoms or dental dams during sex are more likely to have trich.

About 3% of women between the ages of 14 and 49 are estimated to have trich, and as many as 1% of women who have trich have never had sexual intercourse. Studies have indicated that, likely owing to gaps in sexual education along racial lines, African-American women have a higher rate of trich.

Trich prevalence by ethnicity (women 14-49)

African-American 13.30%
Hispanic/Latino 1.80%
White 1.30%

Trich Complications

One of the leading complications involving trich is the frequency with which trich infections are confused for other health issues, such as other infections. For women whose bodies do show symptoms, one of the most common is discolored discharge that’s accompanied by a foul-smelling, fishy odor.

Other issues sometimes mistaken for trich include:

  • Yeast infection, which often causes vaginal discharge
  • Bacterial vaginosis, a common vaginal infection that is not sexually transmitted but can be caused in part by sexual activity
  • Chlamydia and gonorrhea, two very common STDs that can cause unusual vaginal discharge

Symptoms of trich can come and go, but the infection does not resolve on its own. Complications from an untreated trich infection include an increased risk of contracting other STDs, such as HIV, or developing pelvic inflammatory disease, or PID, an infection that can impact a woman’s fertility.

Trich & Pregnancy

STDs during pregnancy, including trich, can be very serious. Pregnant women with trich have higher rates of preterm delivery, and their babies are more likely to be of low birth weight, meaning they weigh less than 5.5 pounds. It’s rare though not impossible for babies to contract trich during pregnancy or childbirth, but those who do can be treated with antibiotics to cure the infection.

Most pregnant women who show no physical signs of trich do not need to undergo routine testing for the STD, but some women who are considered high risk may consider getting tested for trich along with other STDs at least once during their pregnancy.

Trich Testing

Routine testing for trich is generally not recommended for the bulk of the public, though there are a few groups who would benefit from initial and possibly repeated testing:

  • Incarcerated women
  • Sex workers
  • Women with multiple sexual partners
  • Illicit drug users
  • Women with a history of STDs
  • Women with HIV

For people who believe they’ve been exposed to trich, are having symptoms or are in one of the groups at an elevated risk of contracting the infection, there are many options for getting diagnosed, including:

  • Doctor’s office
  • Pharmacy clinic
  • Campus health clinic
  • Community health clinics
  • At-home test kits
  • Urgent care center
  • Planned Parenthood

A trich test usually involves a vaginal swab for women and a urine test for men.

Trich Treatment

Trich is the most common curable STD, and the infection is easily treated with antibiotics, such as metronidazole or tinidazole, usually a single dose. Depending on a person’s overall health status and physiology, a doctor may recommend a lower dose for a longer period.

Those undergoing treatment should refrain from any sexual activity for about 7-10 days to ensure their bodies are fully cured, and they should avoid alcohol for a few days to prevent a potentially unpleasant interaction.

Trich Prevention

As with any STD, the best treatment for trich is prevention. A successful treatment course does not prevent a person from becoming infected in the future, and, in fact, an estimated 1 in 5 people who have been treated for trich get the infection again within three months.

People who are sexually active, including any sexual contact that involves bodily fluids, can lower their risk of getting trich by using condoms or dental dams every time they have sex and ensuring that they only have sex within a monogamous relationship with a person who is not infected with trich or other STDs.


While trich is less scary than some other STDs, it still can lead to potentially serious consequences, including pelvic inflammatory disease, which can impact a woman’s chances of having a baby when she decides the time is right for her. Even in the short term, trich infections are unpleasant and uncomfortable, but using safer sex practices and, if you need to, getting tested and treated can help you avoid this common infection.

Additional References


by AtHomeSTDKit

All content is written by the staff at
If you have any questions about this or other articles, please contact us.