Dehydration

The baby normally retains in the water & salts it need from
drinks & food.
The normally loses water & salts thought stools urine & swet
when the bowel is healthy, water is  salts pass from the bowel into
the blood

Symptoms of   Dehydration 

Thirst isn't always a reliable early indicator of the body's need for water. Many people, particularly older adults, don't feel thirsty until they're already dehydrated. That's why it's important to increase water intake during hot weather or when you're ill.

The signs and symptoms of dehydration also may differ by age.

Infant or young child

Dry mouth and tongue
No tears when crying
No wet diapers for three hours
Sunken eyes, cheeks
Sunken soft spot on top of skull

Listlessness or irritability

Adult

Extreme thirst
Less frequent urination
Dark-colored urine
Fatigue
Dizziness
Confusion

When to see a doctor

Call your family doctor if you or a loved one:

Has had diarrhea for 24 hours or more
Is irritable or disoriented and much sleepier or less active than usual
Can't keep down fluids
Has bloody or black stool