5 weeks old breastfed baby had normal mustardy poops for over 4 weeks but now has greenish yellow with mucus and very watery (like diarrhea) poop and sometimes foamy. he is perfectly fine otherwise. is this normal?

Allergy or infection: Normal infant poops can be yellow, green or brown but should not be foamy or contain mucus. It sounds like your baby may have an allergy or worse case an infection. Try to remove highly allergenic foods from your diet. Cut back on or remove cow’s milk products, soy, wheat, corn, eggs, and peanuts for a few days and see if that helps. If your baby develops a fever (over99.6) at any point, See a DR.

Can be normal: I would recommend you discuss this with your baby’s doctor and also save a diaper with the changed stool so that they can look at it. If your diet has changed or if anyone has a stomach virus, those could be the reasons. The doctor may want to test the stool or do other testing to make sure there is no intestinal absorption problem. If all is fine and baby is growing well, it may not be a problem.