My three week old infant had nausea and loose motions and on investigations was found to have lactose intolerance. As a mother, I am disturbed to find her ‘intolerant' to mother's milk and wean her away so early.
The gut of the infant may not have enough co-factors to break down the lactose in the milk and the disturbed environs in the colon tends to react and empty out the contents causing loose motions like symptoms. Homoeopathic medicine has good remedies like Lac can, Lac defl, Bryonia, Ars alb etc. to see that the gut responds better to the lactose and finds itself fit enough to breakdown lactose when the symptoms correspond. Consult a Homoeopath.