Quick answer
Chlamydia is curable with antibiotics, and treatment is short and highly effective. The two main options are doxycycline (100 mg twice a day for 7 days) and azithromycin (a single 1 g dose). Current CDC guidelines prefer doxycycline for most people because it works slightly better — especially for rectal infections — while azithromycin stays the preferred choice in pregnancy and when finishing a 7-day course is unrealistic. Whichever you take, you should avoid sex until 7 days after treatment, and your recent partners need treatment too or you can be reinfected.
The two first-line antibiotics
| Doxycycline | Azithromycin | |
|---|---|---|
| Dose | 100 mg, twice daily, 7 days | 1 g, single dose |
| Status (CDC 2021) | Preferred for most adults | Alternative; preferred in pregnancy |
| Best for | Rectal chlamydia; reliable cure | One-and-done; poor follow-through; pregnancy |
| Main downsides | Must remember 7 days; sun sensitivity; take upright with water | Slightly higher failure rate for rectal infection; GI upset |
Both are inexpensive, widely available, and don't require an injection.
Why guidelines now lean toward doxycycline
For years, the single-dose azithromycin was the go-to because it's so convenient — you can even take it in the clinic. But newer evidence showed doxycycline cures chlamydia at a slightly higher rate, and the difference is biggest for rectal infections, which are common and often silent. So in its 2021 STI Treatment Guidelines, the CDC moved doxycycline to the recommended regimen and azithromycin to an alternative.
That said, azithromycin is still a good, effective option — and it's the preferred choice during pregnancy, and a sensible one if you're unlikely to complete a full week of pills.
What to expect during treatment
- Take it as directed. For doxycycline, finish all 7 days even if symptoms clear up early. For azithromycin, the single dose is the whole course.
- Doxycycline tips: take with a full glass of water, stay upright for ~30 minutes, and use sunscreen — it can make your skin burn faster.
- Mild side effects like nausea or stomach upset are common with both and usually pass.
- Symptoms fade within a week or two. If you still have discharge, pain, or burning after that, contact your clinician.
When is it safe to have sex again?
Wait 7 days after you finish treatment:
- If you took the single-dose azithromycin, that's 7 days from the day you took it.
- If you took doxycycline, that's 7 days after your last pill (so about two weeks from your first dose).
Just as important: your sexual partners from the last 60 days need treatment too. If they aren't treated, you can simply catch chlamydia again from them — this is the most common reason a "cured" infection comes back.
Do you need a re-test?
- Test of cure (re-testing to confirm it's gone) isn't routinely needed for non-pregnant adults who took the right antibiotic and finished it — these treatments are that reliable. It is recommended in pregnancy.
- Re-testing for reinfection at about 3 months is recommended for everyone treated, because catching it again is common. This is different from a test of cure — it's checking for a new infection, not treatment failure.
When to talk to a clinician
Reach out if you're pregnant, if symptoms don't improve within a week or two, if you have fever or pelvic/testicular pain (which can signal the infection has spread), or if you're unsure whether your partners have been treated. Untreated chlamydia can lead to serious complications like pelvic inflammatory disease and fertility problems — but caught and treated, it's straightforward to cure.
For more, see our chlamydia hub, our overview of STI testing, and — if you've just had a positive result — just diagnosed.
This article is for education and is not a substitute for professional medical advice. Always discuss treatment with a qualified clinician.
