Simply put, 7 10 days is the “Goldilocks number”: It's not so brief a span that the bacterial infection will shake it off, but it's also not long enough to cause an adverse reaction.24 Jan 2012
Can I take 2 lots of antibiotics?
There's an increased risk of side effects if you take 2 doses closer together than recommended. Accidentally taking 1 extra dose of your antibiotic is unlikely to cause you any serious harm. But it will increase your chances of getting side effects, such as pain in your stomach, diarrhoea, and feeling or being sick.