When a person is "infectious", it means they're able to pass their infection on to others.
How long you remain infectious for after starting a course of antibiotics varies. Depending on the infection and how it's treated, it can take between 48 hours and 14 days to stop being infectious.
For example, the antibiotics may take longer to work if your body takes longer to absorb them, or if you're taking other medicine that interacts with the antibiotics.
Medical advice
Talk to a pharmacist or GP if you have any questions or concerns about your course of antibiotics.
It's important to finish your course of antibiotics, even if you're no longer infectious and feeling better. Not finishing the course may result in the infection returning.