how long does it take for penicillin to work

Penicillin begins working immediately after you start taking it, but you typically won't feel better until about 1 to 3 days later. The exact timing depends on the type and severity of the bacterial infection being treated. For common infections like strep throat, improvement is usually seen within a couple of days. However, it's important to complete the full prescribed course of penicillin, often lasting 7 to 14 days, even if you start feeling better sooner. This ensures that all bacteria are eliminated and reduces the risk of antibiotic resistance or infection recurrence. Taking penicillin with food can help reduce side effects like nausea but may slightly delay absorption without significantly impacting effectiveness. If symptoms do not improve within 3 to 5 days or worsen, contacting a healthcare provider is advised. Overall, while penicillin starts killing bacteria promptly, symptom relief and full recovery may take a few days to a week or more depending on the infection.