Bumper/Lilkel - i've copied and pasted this info from an article i have on this subject, read it over then we can disect it if you want.
Your chances of suffering from allergy are much higher if allergy 'runs in the family'. A baby born of one allergic parent has a 20-40% chance of being allergic; a baby born of two allergic parents has a 40-60% chance. However this does not mean that a baby born to non-allergic parents can not have any allergies.
Lactose sugar requires the enzyme, lactase, in the gut to digest it. In very rare instances the baby does not produce any lactase. This mens that baby does not produce sufficient lactase to cope with very large feeds. As a result undigested lactose sugar is left in the gut to ferment causing pain (colic) and sometimes diarrhoea. Smaller, more frequent feeds (requiring less lactase to digest), the addition of a lactase supplement (such as Colief) to expressed breast milk, or a lactose free formula milk should solve the problem.
Colicky babies cry continuously, even when they are fed, warm and dry and so are presumably continuously in pain. Assuming that there are no other obvious problems, then food intolerance may be the answer. And for a newborn that can only be an intolerance to the milk it is drinking.
However, colic is not exclusive to bottle fed babies; sensitive breast fed babies can react to cow's milk and other proteins in their mothers' milk so it is important that in this case the mother too follows a strict cows milk free diet.
For bottle fed babies, the problem is most likely to be an allergy to cow's milk proteins. If full time breast feeding is not an option then experiments with alternative formulae (see below) would be in order. However, it is worth noting that around 30% of cow's milk intolerant/allergic babies will also be allergic to soya so it may be better to go for a hydrolised formula.