The stools of babies are made of a mixture of undigested food, waste
products of the body, bacteria, mucus, cells shed from the lining of the gut,
and water.
Their colour is due primarily to certain bile pigments which are
naturally excreted in the stool.
The bulk and consistency of the stools is determined largely by the
balance between the amount of water and ‘non-digestible’ material (which holds
water and makes the stools moist) within them.
The amounts of water and non-digestible material in the stools (and
hence their size, and consistency) is affected by the milk and/or food that the
baby is taking.
There is a relatively wide variation in what is normal, in terms of
colour, size, shape, consistency and frequency.