I’ve mentioned how important it is to drink a lot of fluids in a number of places throughout this website and the reason for that is a high risk for dehydration. Dehydration is the loss of fluids and electrolytes. There’s a higher risk of dehydration in hot climates and/or if you’ve been sweating a lot.
Ileostomates are at a high risk for dehydration because the colon is the organ that absorbs water and electrolytes back into the body. Without a colon absorbing fluids, fluids go right through you and can leave you dehydrated. As your body adjusts over time, your small intestine may start absorbing some fluids and picking up the slack. Colostomates should also make every effort to stay well-hydrated, especially those missing most of their colon who tend to have looser output.
Diarrhea can be a huge cause for dehydration since you’re losing liquids at such a quick pace.
If you find yourself dehydrated, you can combat it by increasing your fluids. 
Drinking fluids that also include electrolytes will help reverse the dehydration faster. Some good sources of replenishing fluids (especially sodium and potassium) are Nuun tablets, Pedialyte, broths, tomato juice, and milk. You can also rebalance your electrolytesby eating foods high in sodium and potassium such as bananas, potatoes, and other high-potassium vegetables.
It is possible to get so dehydrated you can’t get yourself back on track on your own, at which point you’ll want to go to the ER or Urgent Care for IV fluids. This is usually signified by vomiting and not being able to keep fluids down. At this point you have to suck it up and call your doctor.
Symptoms of dehydration include:
Thirst
Dry mouth and skin
Decreased urine output
Dark urine
Fatigue
Shortness of breath
Stomach cramps
Headaches or Light-headedness
Dry eyes
Electrolyte imbalances show themselves in low sodium and low potassium. Both sodium and potassium are absorbed in the colon, so ileostomates have a higher chance of having their electrolytes get out of whack.
Some symptoms of low sodium include:
Loss of appetite
Drowsiness
Headaches
Abdominal and Leg Cramping
Some symptoms of low potassium include:
Muscle weakness
Cramping
Irregular heartbeat
Shortness of Breath
Fatigue