it’s not a bad idea to do more research if you see mucus in your stool. Some causes are short-lived and may resolve on their own, like if you have had a bout of diarrhea or constipation.

Rectal discharge, or anal discharge, can appear as anal mucus, pus, or blood in stools or underwear. There are many possible causes of rectal discharge, including gastrointestinal conditions ...

How do you know what's normal ... contain blood or mucus or seem to be causing pain. Diarrhea can be more difficult to detect because a baby's stool is naturally loose and unformed.