How long does strep throat last?
Last updated September 3, 2026.
With antibiotics, strep throat improves within 1 to 3 days and you stop being contagious 12 to 24 hours after the first dose; untreated, it runs 3 to 7 days but keeps you contagious for weeks and risks rheumatic fever. That complication - which can permanently damage heart valves - is why testing and treating beats riding it out. During the illness: acetaminophen or ibuprofen, warm salt-water gargles, fluids, and soft foods, plus a fresh toothbrush after a day or two on antibiotics. Get seen urgently if you cannot swallow fluids, develop a muffled hot-potato voice or trouble opening your mouth, or a sandpaper rash appears. Pymander is a free AI doctor, 24/7 by text, and can help you track the course.
What to do
- Expect improvement in 1 to 3 days on antibiotics: no change by then warrants a call back.
- Stay home the first 12 to 24 hours of treatment: contagiousness ends there, not at day 7.
- Finish all 10 days if prescribed: the heart-valve risk only clears when the bacteria do.
- Watch for abscess signs: muffled voice, one-sided swelling, trouble opening your mouth.
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