The most typical causes of dehydration in new born babies are gastrointestinal infections. Dehydration is not an illness as such but is a condition that comes about because of fever, vomiting, diarrhoea, and sweating. It is more common amongst bottle babies due to viral or bacterial infections. Disease such as thrush is also a common cause of dehydration amongst babies because they are unable to drink bottle or being breastfed as a result of the pain in their mouths and throats.