Question: Why do I always finish the bottle / box started ?

Matt Bilton answered on 19 Nov 2014:

Well when we’re infected with some sort of bacteria, we might be prescribed antibiotics. These may kill the bacteria, or even just freeze them to give our immune system the best chance of getting rid of them!

As we are attacking the bacteria with the antibiotics, they will continue to divide – even though lots of them are being affected. Every time the bacteria divides it has to replicate all of its DNA – and often the bacteria will make mistakes! These mistakes can weaken the bacteria, or sometimes make it stronger.

When faced with antibiotics, the strongest bacteria are the ones that can survive in the presence of the drug the longest. Eventually they may be killed by the antibiotics and the immune system, but if the antibiotics are stopped early, even if you feel better, some of the stronger bacteria may survive. This could be a big problem because they are the ones the antibiotics affect the least. So when these bacteria replicate, they will cause you to be ill again and they may all be resistant to the antibiotics as well!

On the other hand, if we finish the antibiotics so that all the bacteria are killed, we avoid encourage the spread of antibiotic resistant bacteria! So this is why it’s import to always finish your course of antibiotics 🙂