Is green snot a bacterial infection?

What the evidence says

Green or yellow snot does not automatically mean your child has a bacterial infection. The Canadian Paediatric Society says it is common for mucus to turn thick and colored, yellow or green, during a regular cold, and this does not need antibiotics.

Here's what's actually happening: as your child's immune system fights off the cold virus, white blood cells rush to the nose. These cells contain a greenish enzyme, and when a lot of them build up in the mucus, it turns yellow or green. This is just a sign the immune system is doing its job, not proof that bacteria are involved.

A study looking at children with sinus infections found that green discharge was somewhat more common in kids with bacterial sinusitis, but it also showed up in plenty of kids with ordinary viral colds. Doctors do use colored, thick discharge as one clue among several, but never the only one.

What actually points more toward a bacterial infection needing treatment is how long the symptoms last and how severe they are. Canadian guidance says to call the doctor if the colored discharge lasts more than 10 to 14 days, or if your child seems very sleepy, won't eat or drink, or is inconsolably fussy.

So green snot by itself is not a reason to ask for antibiotics. Keep an eye on the whole picture: how long it's lasting, fever, energy level and feeding, and check in with your doctor if those other signs show up.