my son is 18months old now,he is having blood content in his poop

A. hi dear A common cause of blood in an infant's stool is a slight anal tear (fissure) from baby straining with the passage of the stool. The small amount of blood from an anal fissure tends to look like a red streak on the outside of the stool. Another common cause of blood in the stools of infants is food allergies.