Why do I get yeast infections after antibiotics?

This is one of the most predictable side effects in medicine, and the mechanism is straightforward ecology. MedlinePlus explains that candida - a fungus most women carry in small amounts - normally lives in balance with the other germs in the vagina, and that antibiotics used to treat another infection change that balance, letting candida numbers climb into a yeast infection. The antibiotics are not targeting your vaginal bacteria, but they cannot tell the protective lactobacilli from the throat bug they were prescribed for - so the guard population drops, and the yeast, which antibiotics do not touch, expands into the space. The result, per the NHS's thrush symptom list: itching and irritation around the vulva and vagina, stinging when you pee or during sex, and a white discharge that is often compared to cottage cheese and does not usually smell. It tends to announce itself during the course or within days of finishing it. The practical points: this is treatable without fuss - a pharmacist can supply an antifungal cream or pessary, and you do not need to stop the antibiotic (but do tell whoever prescribed it if symptoms are severe). If you get a yeast infection with nearly every antibiotic course, say so before the next prescription - sometimes a narrower-spectrum choice or a pre-emptive antifungal is sensible. See a GP rather than self-treating if it keeps recurring, if the discharge smells or changes colour, if you have pelvic pain or fever, or if you are pregnant - those change the diagnosis list. Pymander is a free AI doctor, 24/7 by text, that can help you decide which route fits.