Seeing blood streaks in a baby's stool is distressing and should always be discussed with your pediatrician to rule out infections. While infections can cause blood and mucus, in some babies with CMPA or a sensitive gut, solids—even simple ones like moong dal, apple, or banana—can trigger a temporary inflammatory response. This doesn't necessarily mean a permanent allergy; it often indicates the gut is still maturing. Pediatricians may suggest pausing the new food, allowing the gut to heal (sometimes with a probiotic), and reintroducing the item in a smaller quantity after a few weeks.