Strep throat is treated with antibiotics, and the recommended choices are penicillin or amoxicillin. These have been the go-to medications for decades because group A strep bacteria have never developed resistance to them. A full course lasts 10 days, and finishing every dose matters even after you start feeling better.
First-Line Antibiotics
Amoxicillin is the most commonly prescribed option, partly because it comes in a liquid form that’s easier for children and tastes better than penicillin. For adults and adolescents, penicillin V is typically prescribed at 500 mg twice daily for 10 days. Children usually take 250 mg two or three times daily for the same duration.
Amoxicillin can be taken once daily or split into two doses, which many people find more convenient. Both antibiotics work equally well at clearing the infection. Your provider may also offer a one-time penicillin injection, which eliminates the need to remember pills for 10 days. This is sometimes preferred for people who have trouble completing a full oral course.
Options if You’re Allergic to Penicillin
If you have a penicillin allergy, several alternatives exist, but the right one depends on the type of allergic reaction you’ve had. People whose allergy caused a rash (a delayed reaction) can usually take a related antibiotic called cephalexin safely. It’s taken twice daily for 10 days.
If your allergy involved swelling, hives, or difficulty breathing (an immediate reaction), cephalexin is off the table because it’s chemically similar to penicillin. In that case, the options include clindamycin, taken three times daily for 10 days, or azithromycin, which has a shorter five-day course. Azithromycin is a larger dose on day one, then a smaller dose for the remaining four days. Clarithromycin, taken twice daily for 10 days, is another choice in this category.
Over-the-Counter Pain Relief
Antibiotics kill the bacteria, but they won’t make your throat feel better right away. Most people notice symptom improvement within two to three days of starting antibiotics, which means you’ll want something for pain in the meantime. Ibuprofen (Advil, Motrin) and acetaminophen (Tylenol) both reduce throat pain and fever effectively. You can alternate between the two if one alone isn’t enough.
For severe throat pain, there’s evidence that a single dose of a steroid given alongside antibiotics can speed things up significantly. A meta-analysis published in The BMJ found that patients with severe sore throat who received a steroid in addition to antibiotics were three times more likely to have complete pain relief within 24 hours. Steroids also cut the time to initial pain relief by about six hours. This isn’t something you’d pick up over the counter, but if your pain is intense and swallowing is very difficult, it’s worth asking about.
Why Finishing All 10 Days Matters
You’ll likely feel much better within a few days of starting antibiotics, but the bacteria aren’t fully eliminated that quickly. Stopping early gives surviving bacteria a chance to rebound, which can lead to a second, harder-to-treat infection. More importantly, incomplete treatment raises the risk of rheumatic fever, a serious inflammatory condition that can damage heart valves. Severe rheumatic heart disease can require surgery and can be fatal. Untreated or undertreated strep can also lead to kidney inflammation.
These complications are uncommon in people who complete their antibiotics, which is exactly why finishing the full course is so important.
How Quickly You Stop Being Contagious
Once you’ve taken your first dose of antibiotics, you’re generally no longer contagious within 12 hours. Schools and daycares use this same 12-hour rule for readmission. Without antibiotics, strep throat remains contagious for two to three weeks, even as symptoms fade. This is one reason treatment matters beyond just feeling better: it protects the people around you.
Getting the Right Diagnosis First
Strep throat can’t be diagnosed by symptoms alone because viral sore throats look nearly identical. A rapid strep test takes about 10 minutes and is highly accurate when positive. If it comes back negative, the next step depends on age. For children over 3, a negative rapid test should be followed up with a throat culture, which takes one to two days but catches cases the rapid test misses. For adolescents and adults, a throat culture after a negative rapid test generally isn’t necessary.
Getting tested before starting antibiotics matters because taking antibiotics for a viral sore throat won’t help, and it contributes to antibiotic resistance. Current clinical guidelines from the Infectious Diseases Society of America, updated in 2025, recommend using a scoring system to determine which patients even need testing, since many sore throats are low-risk for strep and don’t benefit from testing or treatment.