Strep Throat Treatment for Adults: Antibiotics, Recovery Time and When You Stop Being Contagious

Written by Naurah Gaspard, DNP, FNP-C, FNP-BC · Medically reviewed by Cherlie Joseph, MSN, FNP-BC · Updated November 2026

Strep throat is treated with a prescription antibiotic, most often penicillin or amoxicillin taken for 10 days. Most adults feel noticeably better within 2 to 3 days of starting treatment, and you are generally no longer contagious once you have no fever and have been on the antibiotic for at least 12 to 24 hours. A positive strep test should come before antibiotics, because most sore throats in adults are caused by viruses.

First, confirm it is really strep

Strep throat is a bacterial infection caused by group A Streptococcus. It is far less common in adults than in children; most adult sore throats come from the same viruses that cause colds. That matters because antibiotics do nothing for a virus and can cause side effects like diarrhea, yeast infections and allergic reactions.

The CDC advises that people with clearly viral symptoms, such as a cough, runny nose, hoarse voice, mouth sores or pink eye, usually do not have strep and do not need a strep test. Strep is more likely when you have:

• A sudden, painful sore throat and pain with swallowing
• Fever
• Red, swollen tonsils, sometimes with white patches or streaks of pus
• Tiny red spots on the roof of the mouth
• Swollen, tender lymph nodes in the front of the neck
• No cough or cold symptoms

Because these signs overlap with viral infections, a rapid strep test or throat culture is the only way to know for sure. For adults, the CDC says a negative rapid test usually does not need a backup culture. If you are unsure which type you have, our guide to strep vs. viral sore throat walks through the differences.

Antibiotics used for strep throat

Group A strep has never been shown to be resistant to penicillin, which is why penicillin-family drugs remain first choice in CDC and Infectious Diseases Society of America guidance.

Antibiotic	Usual course	Notes
Penicillin V (pills)	10 days	First-line; taken two to four times a day
Amoxicillin	10 days	First-line; can be taken once or twice a day
Penicillin G benzathine (shot)	One injection	Given in person; useful if taking pills for 10 days is hard

Finish the full course even when you feel better on day 3. Stopping early is the main reason symptoms come back, and full treatment is what lowers the risk of rare complications such as rheumatic fever and kidney inflammation. Your provider will choose the dose based on the medication label and your health history.

If you are allergic to penicillin

Tell your provider exactly what happened when you reacted to penicillin, because the right alternative depends on the type of reaction:

• Mild, delayed reaction (such as a non-itchy rash days later): a first-generation cephalosporin such as cephalexin or cefadroxil for 10 days is often an option.
• Immediate reaction (hives, swelling, trouble breathing or anaphylaxis): the CDC advises avoiding cephalosporins. Clindamycin for 10 days or azithromycin for 5 days are common alternatives.

Resistance to azithromycin and clindamycin does occur in the United States and varies by region, which is one reason these are second choices rather than first. Many people who were told they had a penicillin allergy as a child are not truly allergic; allergy testing later can open up first-line options.

Recovery timeline and when you stop being contagious

• Day 1 to 3 of antibiotics: fever usually breaks and throat pain starts easing.
• After 12 to 24 hours of antibiotics with no fever: the CDC says most people can return to work or school. Health care workers, or anyone in an outbreak setting, may be asked to stay home a full 24 hours.
• Days 4 to 10: keep taking every dose. Mild throat soreness can linger for a few days.

Strep spreads through respiratory droplets and shared cups or utensils. Wash your hands often, do not share drinks, and consider replacing your toothbrush once you have been on treatment for a day or two. Without antibiotics, a person can stay contagious for weeks.

If you are not improving after 48 to 72 hours on an antibiotic, or you feel worse, contact your provider. That can signal a different diagnosis or a complication such as an abscess near the tonsil.

Feeling better at home while the antibiotic works

• Take acetaminophen or ibuprofen as directed on the label for pain and fever, unless your provider has told you to avoid them.
• Gargle with warm salt water (about half a teaspoon of salt in a cup of warm water) a few times a day.
• Drink plenty of fluids. Cold drinks, ice pops and warm broth are all soothing.
• Try throat lozenges or honey in warm tea.
• Rest and use a humidifier at night if the air is dry.

For more ideas, see our sore throat remedies for adults.

Frequently asked questions

Can strep throat go away without antibiotics?

Sometimes symptoms fade on their own within a week, but untreated strep can stay contagious longer and carries a small risk of complications such as a tonsil abscess or rheumatic fever. That is why confirmed strep is treated with antibiotics.

How long after starting antibiotics is strep contagious?

The CDC says most people can return to work or school once they have no fever and have taken an appropriate antibiotic for at least 12 to 24 hours.

Can I get strep throat treated online?

An online provider can review your symptoms, help decide whether a strep test is needed and where to get one, and treat confirmed strep when appropriate. If you have warning signs like trouble breathing or swallowing, you need in-person care.

Sources

• CDC: Clinical Guidance for Group A Streptococcal Pharyngitis
• MedlinePlus: Strep throat
• MedlinePlus: Peritonsillar abscess

Keep reading

• Strep throat vs. viral sore throat: how to tell the difference
• Sore throat remedies for adults
• When to see a provider for a cold
• Browse all conditions and treatments A to Z

This article is for general education and is not a substitute for medical advice. Treatment, including any prescription, is decided by a licensed provider after reviewing your health history. OurTopClinic is not for emergencies; if you have a medical emergency, call 911. OurTopClinic serves adults located in Florida, New Mexico, Oregon and Washington. Learn more at ourtopclinic.com.