Do You Need Antibiotics for a Sinus Infection?
Facial pressure, a stuffed nose and thick green drainage feel like they should need an antibiotic. Usually they do not. Here is how doctors decide, what they prescribe when it is needed, and what helps in the meantime.
Most sinus infections are caused by viruses and get better on their own, usually within 7 to 10 days. Antibiotics do not help viral sinus infections. Guidelines from the Infectious Diseases Society of America point to three patterns that suggest a bacterial infection: symptoms lasting 10 days or more without improving, severe symptoms with a high fever for 3 to 4 days in a row, or getting worse after you started to get better. When an antibiotic is needed, amoxicillin-clavulanate is the usual first choice.
- Green or yellow mucus on its own does not mean you need an antibiotic.
- Saline rinses and a steroid nasal spray are the most useful home treatments.
- Azithromycin (Z-Pack) is not a recommended first choice for sinus infections because of resistance.
- When antibiotics are used for adults, IDSA guidelines suggest a 5 to 7 day course.
- Swelling around the eye, a severe headache or a stiff neck needs care right away.
Why most sinus infections are viral
The sinuses are air-filled spaces behind the face. When a cold virus inflames the nose, the sinuses swell and fill with mucus, which causes pressure, congestion and drainage (MedlinePlus). The CDC notes that many sinus infections get better on their own and do not need antibiotics, and that antibiotics taken when they are not needed can still cause side effects (CDC).
Thick yellow or green mucus is part of the normal immune response to a virus. It is not, by itself, a sign of a bacterial infection.
The three signs it may be bacterial
The IDSA guideline for acute bacterial sinusitis describes three patterns that make a bacterial infection more likely (PubMed):
- Persistent: symptoms last 10 days or more without any improvement.
- Severe: a fever of 102.2°F (39°C) or higher with thick nasal discharge or facial pain for 3 to 4 days in a row at the start of the illness.
- Double sickening: you started to get better from a cold, then got worse again with new fever, headache or more discharge.
If none of these fit, an antibiotic is unlikely to help, and symptom relief is the right treatment.
Which antibiotic, and for how long
- Amoxicillin-clavulanate (Augmentin) is the first-line choice in the IDSA guideline.
- For people allergic to penicillin, a provider will choose a different antibiotic, such as doxycycline.
- Azithromycin and other macrolides are not recommended as first choices because many of the bacteria that cause sinus infections are resistant to them. Our Z-Pack guide covers what azithromycin is used for.
- For adults, the guideline suggests 5 to 7 days of treatment for an uncomplicated infection.
Common antibiotic side effects include diarrhea and upset stomach. Tell the provider about any allergies and other medicines you take.
Relief that actually helps
- Saline rinses or sprays wash out mucus and ease congestion.
- A steroid nasal spray such as fluticasone (also sold OTC as Flonase) reduces swelling, especially for people with allergies.
- Pain relievers like acetaminophen or ibuprofen for facial pain and headache.
- Warm compresses, steam and plenty of fluids.
- Decongestants and antihistamines are not recommended by IDSA as an add-on treatment for a bacterial sinus infection. If you use a decongestant nasal spray for a cold, do not use it for more than 3 days, as it can cause rebound congestion.
Viral vs bacterial at a glance
| Viral (most cases) | Bacterial (less common) | |
|---|---|---|
| How long | Usually improves within 7 to 10 days | 10+ days without improving, or worse after improving |
| Fever | Low or none | Can be high (102.2°F or more) early on |
| Mucus color | Often yellow or green | Often yellow or green |
| Antibiotics help? | No | Yes, usually amoxicillin-clavulanate first |
| Best treatment | Saline, steroid spray, pain relievers | Antibiotic plus the same relief measures |
Getting seen
Rx.com's online sinus infection visit is a flat $99 with a U.S.-licensed provider, with no insurance needed. The provider will ask how long you have been sick and how your symptoms have changed. If an antibiotic is right for you, it goes to your local pharmacy. If it is not, you will get a plan for relief instead.
In October 2026 the lowest prices we found on Rx.com were amoxicillin-clavulanate from $13.84 and fluticasone nasal spray from $17.99; prices vary by pharmacy and location. Show a free Rx.com coupon at pickup.
🚨 When to Get Care Right Away
- Swelling or redness around the eye, double vision or vision changes.
- A severe headache, a stiff neck, confusion or unusual sleepiness.
- A high fever that will not come down.
- Symptoms lasting more than 12 weeks, or several sinus infections a year: see a doctor about chronic sinusitis.
Frequently Asked Questions
Will a sinus infection go away without antibiotics?
Most do. Viral sinus infections usually improve within 7 to 10 days with rest, saline rinses and pain relievers.
When should I take antibiotics for a sinus infection?
When a provider thinks it is bacterial: symptoms lasting 10 days or more without improving, a high fever with severe symptoms for 3 to 4 days, or getting worse after starting to get better.
Does green mucus mean I need antibiotics?
No. Green or yellow mucus is common with viral infections and does not by itself mean bacteria are involved.
What is the best antibiotic for a sinus infection?
Amoxicillin-clavulanate is the usual first choice in IDSA guidelines. People allergic to penicillin get a different antibiotic chosen by the provider.
Is a Z-Pack good for a sinus infection?
Azithromycin is not recommended as a first choice for sinus infections because many of the bacteria that cause them are resistant to it.
How long does a bacterial sinus infection take to clear with antibiotics?
Many people feel better within a few days of starting treatment. Adults are commonly treated for 5 to 7 days. If you are not improving after a few days, check back with the provider.
Day 10 and still stuffed up?
See a U.S.-licensed provider online for a flat $99 and find out whether you need an antibiotic or just relief.
Sources
- Chow AW, et al. IDSA clinical practice guideline for acute bacterial rhinosinusitis in children and adults. Clinical Infectious Diseases. 2012. PubMed
- Centers for Disease Control and Prevention. Sinus infection basics. cdc.gov
- MedlinePlus. Sinusitis. medlineplus.gov
