The difference comes down to cause. Bacterial and parasitic STIs — chlamydia, gonorrhea, syphilis, and trichomoniasis — are curable with antibiotics. Viral STIs — herpes, HIV, hepatitis B, and HPV — can't be cured, but medicine controls them well enough that many people live normally and never pass them on.
antibiotics clear them
medicine controls, doesn't cure
| Item | Value |
|---|---|
| Bacterial & parasitic (chlamydia, gonorrhea, syphilis, trich) | curable — antibiotics clear them |
| Viral (herpes, HIV, hepatitis B, HPV) | managed — medicine controls, doesn't cure |
What "bacterial" and "viral" actually mean here
A bacterium is a self-contained, living cell. Antibiotics kill it or stop it from multiplying, so once the drug clears the infection, the organism is gone and you're cured. A virus works differently. It hijacks your own cells to make copies of itself, so there's no separate organism to kill without harming you. Antiviral medicines slow that copying down dramatically, but they don't eradicate the virus from the body.
Trichomoniasis is technically caused by a parasite (a single-celled protozoan), not a bacterium, but it behaves like the bacterial group for our purposes: a specific drug clears it completely. The practical split is curable infections versus manageable ones CDC, 2021.
The curable group: bacterial and parasitic STIs
Chlamydia
Chlamydia is a bacterial infection treated with a short course of oral antibiotics, commonly doxycycline. It's one of the most common reportable STIs and frequently causes no symptoms, so screening picks up what you'd otherwise miss. Doxycycline can cause stomach upset and make your skin burn more easily in the sun, so take it with food and stay out of strong sunlight while you're on it.
Gonorrhea
Gonorrhea is bacterial and is now treated with a single ceftriaxone injection. The main side effect is soreness where the shot goes in. It's an injection and not a pill because gonorrhea has grown resistant to nearly every antibiotic once used against it, and ceftriaxone is the last consistently reliable option CDC drug-resistant gonorrhea. Take the exact recommended drug at the right dose, because sloppy treatment spreads resistance. If you want to understand the diagnostic side, here's how the gonorrhea test works and how to read results.
Syphilis
Syphilis is a bacterial infection cured with antibiotics, classically penicillin. It moves through stages, and untreated it can eventually damage the heart, brain, and nerves, so catching and treating it early matters. Because the stage determines the regimen, a clinician needs to confirm where you are before treating.
Trichomoniasis
Trichomoniasis ("trich") is a parasitic infection treated with metronidazole or tinidazole CDC trichomoniasis treatment. These drugs react badly with alcohol, causing flushing, nausea, and vomiting, so skip alcohol during treatment and for a short window afterward as your clinician directs.
The manageable group: viral STIs
Herpes (HSV)
Herpes is a lifelong viral infection that lives in nerve cells between outbreaks. There's no cure, but antiviral medicine shortens outbreaks and eases pain, and taken daily it sharply lowers how often you flare and how likely you are to pass it to a partner. You can take it only during outbreaks or every day to suppress them; the trade-offs are covered in this guide to herpes treatment.
HIV
HIV is a virus that attacks the immune system. It can't be cured, but daily antiretroviral therapy can suppress it to undetectable levels, at which point it doesn't damage your health and can't be transmitted sexually. Modern treatment turns HIV into a chronic, manageable condition rather than the death sentence it once was.
Hepatitis B
Hepatitis B is a viral infection of the liver. Many adults clear it on their own, but some develop a chronic infection that antiviral medicine controls to protect the liver over time. A vaccine prevents it entirely, the better path if you're not already infected.
HPV
HPV is a virus, and there's no medicine that eliminates it. In most people the immune system clears it on its own over time. When it causes problems — genital warts or precancerous cell changes — those problems are treated directly, but the underlying virus isn't "cured" with a pill. Vaccination prevents the high-risk types that cause most cancers.
Bacterial vs viral STDs at a glance
| Feature | Bacterial / parasitic | Viral |
|---|---|---|
| Examples | Chlamydia, gonorrhea, syphilis, trichomoniasis | Herpes, HIV, hepatitis B, HPV |
| Curable? | Yes — fully cleared | No — controlled, not cured |
| Medicine | Antibiotics (pills or a shot) | Antivirals; sometimes treat symptoms only |
| Typical course | A short course or single dose | Often ongoing or lifelong |
| Vaccine available? | No | Yes for hepatitis B and HPV |
| Do antibiotics help? | Yes | No — useless against viruses |
Antibiotics do nothing against a virus. Taking them for herpes or HIV won't help and only fuels resistance, so the diagnosis has to come first.
Which one applies to you?
You can't tell bacterial from viral by symptoms. They overlap heavily, and many of both kinds cause no symptoms at all. The only way to know what you have, and therefore whether it's curable, is a test that names the specific organism. If you've had a possible exposure, start with knowing when to test after exposure, since testing too early can miss an infection, then go get tested so treatment is matched to an actual diagnosis.
The practical next step: what treatment actually looks like
For the curable infections, treatment is usually undramatic: a short course of pills or a single shot, often free or low-cost at a health department or Planned Parenthood. Many clinics also offer expedited partner therapy, meaning your partners can frequently be treated without their own appointment — the clinician sends medication or a prescription home with you for them.
A few rules make treatment actually work:
- Finish the entire course exactly as prescribed, even after symptoms fade. Most people feel better within a few days, but feeling better is not proof of cure.
- Make sure partners are treated too, or you'll pass it back and forth in a loop.
- Avoid sex until you and your partners have finished treatment plus any wait period your clinician sets — often about a week after a single-dose treatment.
- Skip the home remedies. There is no over-the-counter product that cures a bacterial or viral STI; yogurt, garlic, douching, and "detoxes" don't work. You need the specific prescription and a real diagnosis.
The single most common mistake is stopping early because you feel fine, or skipping partner treatment. Either one lets an infection quietly persist or bounce straight back, sometimes harder to treat than the first time.
When to talk to a clinician
See a clinician if you've had a possible exposure, have new symptoms (discharge, sores, burning, pelvic or testicular pain), or a partner tells you they tested positive. You also need professional care to choose the right drug — especially for gonorrhea, where the wrong medication can fail outright. And some infections need a follow-up test-of-cure or a retest weeks to months later, not just a course of pills, so don't assume "done" until your clinician confirms it.