"Four days and I'm better, the rest can go in the drawer"

The short ones are different, and the honest thing is to say that the advice around them has changed and to be precise about what it's changed to.

For years the message was to always finish the course, because stopping early would breed resistant bacteria. In 2017 a group of infection specialists led by Martin Llewelyn argued in the BMJ that the course-completion message wasn't well supported and that the link between stopping early and resistance runs, if anything, the other way. Spellberg and Rice, reviewing the trials in 2019, counted more than 45 randomised comparisons of shorter against traditional courses across pneumonia, urinary infections, skin infections and others, and found no difference in cure rates. A study of 931,015 antibiotic prescriptions in English general practice found that for most common infections a substantial share of courses were longer than the guidelines recommended, adding about 1.3 million days of antibiotics. So the old dogma is going, and courses are getting shorter by design.

Here's what that does not mean. It does not mean you should stop when you feel better. The current NHS advice is to take antibiotics as directed on the packet or the leaflet, or as your GP or pharmacist instructed. The reason is that the shortening is happening at the prescriber's end. A five-day course written in 2026 is already the shorter course. The prescriber chose its length for your infection, and day four of five isn't a judgement you can improve on from the sofa, because feeling better and being clear of the infection aren't the same event, and the day they diverge varies by infection. If you feel better and you'd like to stop, ring the surgery or ask a pharmacist. For some infections the answer will be yes, and it will be a yes from someone who knows which infection it was.

The other half of this chapter is the drawer. A review of 46 studies found that people took about 62 percent of their antibiotics as prescribed and that about 29 percent later used leftovers, for the next sore throat or the next child. That's the most dangerous thing the drawer does, because the leftover is the wrong antibiotic at the wrong dose for an infection nobody's diagnosed. The NHS says unwanted medicines go back to the pharmacy. Not the bin, not the toilet, and not the drawer.