Hi, my name is Windy St. George, and this is how to spot signs of illness in your newborn. The most important sign, is a loss of appetite. If the baby is not eating as much as normal, especially if the baby is groggy, or listless, or hard to wake up, the baby is probably sick. Check for a temperature. If it is above 101, you're going to have to call the doctor. If it's below that, the child probably just has a cold,or a virus. You should monitor the situation, and give the baby Tylenol, if it's safe for that baby's age. You can consult your pediatrician about medication procedures. If the child changes color in skin, sometimes they will get very bright red in the cheeks, and you know they probably have a fever. If the baby turns yellow, it might be jaundice. If it's a newborn, definitely check with your pediatrician, right away in that case. Problems with diaper, they could be constipated or they could have runny, loose stools, that happen more frequently than usual. The baby is probably sick, and you should give him more fluids, and plenty of rest. If your baby is cranky and fussy, and having a hard time breathing, making kind of a sound when he breathes, or doesn't want to lay down, and he's uncomfortable, he might be congested. You should take him in the shower and let him breathe hot, steamy air, for about ten minutes. You could try saline drops in the nose, too.