Four sexually transmitted infections are currently curable: chlamydia, gonorrhea, syphilis, and trichomoniasis. The first three are caused by bacteria, and the fourth by a parasite. All four can be eliminated from your body with the right course of antibiotics or antiparasitic medication, often in a single dose or a short treatment course. The four viral STIs, by contrast, are treatable but not curable: HIV, herpes (HSV), hepatitis B, and HPV.
Chlamydia
Chlamydia is one of the most common STIs worldwide and one of the easiest to cure. The standard treatment is a week-long course of oral antibiotics taken twice daily. An alternative is a single oral dose of a different antibiotic, which is also the preferred option during pregnancy. Most people have no symptoms at all, which is why routine screening matters. Left untreated, chlamydia can cause pelvic inflammatory disease in women and fertility problems in both sexes.
Testing is reliable as soon as one week after exposure, with two weeks catching almost all infections. After treatment, retesting about three months later is recommended because reinfection is common, especially if a sexual partner wasn’t treated at the same time.
Gonorrhea
Gonorrhea is curable, but it has become harder to treat over time. The bacteria that causes it has developed resistance to nearly every class of antibiotic ever used against it. Fluoroquinolones, once a go-to option, were dropped from U.S. guidelines in 2007 after widespread resistance emerged. Today, only one antibiotic class (cephalosporins) remains reliably effective, and the current standard treatment is a single injection.
Resistance to the remaining antibiotic has stayed low so far, with less than 0.1% of tested samples showing decreased susceptibility in 2019. But the narrowing of treatment options is a serious concern. For throat infections specifically, no reliable alternative treatments exist if the first-line drug can’t be used. If your test also hasn’t ruled out chlamydia, you’ll typically be treated for both infections simultaneously, since they often occur together.
Like chlamydia, gonorrhea testing becomes reliable about one to two weeks after exposure.
Syphilis
Syphilis is curable with penicillin, the same drug that’s been used against it since the 1940s. For early-stage syphilis (primary, secondary, or early latent), a single injection is the standard treatment, with studies reporting success rates of 90% to 100%. The earlier you catch it, the better the outcome. One study found that 100% of patients with primary syphilis who hadn’t yet developed antibodies were cured at 12 months, while 94.5% of those with secondary syphilis were cured at two years.
Late-stage syphilis is a different picture. If the infection has been present for a long time without treatment, cure rates drop significantly. Late latent syphilis responds to penicillin only about 56% to 63% of the time, and treatment requires three weekly injections instead of one. Syphilis that has spread to the nervous system, eyes, or ears needs intravenous treatment over 10 to 14 days. The takeaway: syphilis is highly curable, but timing matters enormously.
Trichomoniasis
Trichomoniasis is the only curable STI caused by a parasite rather than bacteria. It’s treated with antiparasitic medication taken by mouth. Treatment differs slightly between men and women. Men typically receive a single large dose, while women take a smaller dose twice daily for seven days, which clinical trials show produces better results for women. Cure rates range from 84% to 98% with the standard regimen, and an alternative medication achieves 92% to 100%.
Trichomoniasis is often overlooked because many people, especially men, have no symptoms. Women may experience unusual discharge, itching, or discomfort during urination. Testing can pick up the infection about a week after exposure, though waiting a full month catches almost all cases.
Why Viral STIs Can’t Be Cured
The four incurable STIs (HIV, herpes, hepatitis B, and HPV) are all caused by viruses, and viruses behave fundamentally differently from bacteria and parasites. They insert their genetic material into your own cells, creating hidden reservoirs that antibiotics simply can’t reach.
Herpes is a lifelong infection. The virus retreats into nerve cells between outbreaks, where it stays dormant. Antiviral medications can reduce the frequency and severity of outbreaks and lower the risk of transmitting the virus to a partner, but they don’t eliminate the dormant virus. Once medication stops, it has no lasting effect on future outbreaks.
HIV, if untreated, progressively destroys immune cells over years, eventually leading to AIDS. Modern antiviral therapy suppresses the virus to undetectable levels, provides a near-normal lifespan, and prevents sexual transmission. But it requires lifelong daily medication because the virus persists in a latent state within immune cells.
Hepatitis B can be managed with antivirals that slow liver damage, and HPV infections often clear on their own within a couple of years, though the virus can persist and cause problems like genital warts or, in some cases, cancer. Vaccines exist for both hepatitis B and HPV, making prevention especially important for infections that can’t be cured after the fact.
Cured Doesn’t Mean Immune
One critical point that catches people off guard: curing a bacterial or parasitic STI does not give you any immunity to it. You can be reinfected the next time you’re exposed. This is why treating sexual partners matters as much as treating the person who tested positive. If your partner still carries the infection, you’re likely to get it right back.
For chlamydia and gonorrhea, a practice called expedited partner therapy allows your doctor to provide a prescription or medication for your partner without requiring them to come in for a separate visit. This is especially useful when a partner is unlikely to seek care on their own. The CDC considers it a valuable tool for preventing the reinfection cycle, particularly for male partners of women diagnosed with chlamydia or gonorrhea.
Testing Windows for Curable STIs
Getting tested too soon after exposure can produce a false negative. Each infection needs time to build up to detectable levels. Chlamydia and gonorrhea are reliably detected one to two weeks after exposure. Trichomoniasis can take up to a month to show on a test, though most cases are detectable within a week. Syphilis has a longer window and may take several weeks to produce a positive blood test, depending on the stage.
If you’re concerned about a specific exposure, testing at two weeks will catch most chlamydia and gonorrhea infections. For trichomoniasis and syphilis, waiting a bit longer improves accuracy. Retesting after treatment, typically at the three-month mark for chlamydia and gonorrhea, confirms the infection is gone and checks for reinfection.