One would assume that with all the milk babies drink that they don't need any more fluids. But because babies have relatively small fluid reserves and high metabolic rates, they can easily lose electrolytes and water, which are crucial for their little bodies to function. And if your baby is having a bad bout of diarrhea, she'll also be susceptible to becoming dehydrated more quickly than usual.
Dehydration is reversible, but it's important to take action as soon as possible. If a baby's fluids aren't replenished over a long period of time then it even be fatal. Here are some important signs to watch for to know if your baby is dehydrated.