My baby is 7 month old today morning he was having hard time passing the stool. I noticed bit of red dot and streaks on his poop. Usually he poops everyday 1 or 2 times but he didn't poop yesterday he was trying but he couldn't. I introduced him to yogurt a day before. He had that kind of poop a week before as well but without any redness. Can this be due to milk allergy or just some foods causing it such as banana, avocado or broccoli?

Thank you everyone