[A 6-day-old girl with weight loss]. 
Newborn children normally lose up to 10% of their birth weight during the first week of life.  With greater weight loss one must consider low intake and pathological losses.  We describe a 6-day-old girl with nearly 19% weight loss and hypertonic dehydration caused by hypogalactia.  Principles for treatment of hypertonic dehydration and strategies for finding these children are discussed.