Your body needs the right amount of water and minerals to function properly. You lose body fluids during the day through sweat, tears, moisture in your breath, pee and poo. Usually, the fluid and salt content of what you eat and drink make up for this loss. But you can become dehydrated if you lose more fluid than you take in.

This can happen for a number of reasons. Not drinking enough water or fluids or losing too much body fluid through sweating, vomiting or diarrhoea, can cause dehydration.

When your body is dehydrated, this can cause you to lose weight due to there being less water in your body. Dehydration can be described as mild, moderate or severe depending on how much of your body weight has been lost through fluids.

Feeling thirsty and dark yellow pee are two early signs that you may be dehydrated.

Other symptoms of dehydration include:

• Not peeing as much as usual
• Strong smelling pee
• Headache
• Feeling dizzy
• Dry or cracked lips, tongue and mouth

Dehydration may not be a problem for everyone with Crohn’s or Colitis. However, you may be more likely to become dehydrated if you:

• Have frequent or watery diarrhoea
• Are being sick (vomiting) repeatedly
• Have had your colon removed or have had ileal pouch-anal anastomosis (IPAA) surgery, commonly known as J-pouch surgery
• Have a stoma (ileostomy)
• Have short bowel syndrome. Short bowel syndrome happens when the bowel does not have enough surface area to absorb nutrients from your food and drink. This can happen if you have had surgery to remove large sections of your small bowel.
• Have bile salt malabsorption, which can cause frequent watery diarrhoea
• Are sweating a lot. This might be during hot weather or exercise, or because you have a fever.
• Are peeing more than usual. This can happen if you have uncontrolled diabetes, are drinking too much caffeine, or are taking diuretic medicines (‘water tablets’ which make you pee more).
• Have drank too much alcohol
• Are being sick or have diarrhoea because of a stomach bug (gastroenteritis), bowel infection or food poisoning

If you have symptoms of dehydration, drink plenty of fluids. This could be water or diluted squash. Keep drinking small amounts of fluids regularly. Avoid caffeine or alcohol as they can make dehydration worse.

If you have been sick (vomiting) or have diarrhoea, you might need to increase the levels of salts and sugar in your body, as well as water. Oral rehydration solutions (ORS) are powders or tablets that are dissolved in water. They help the body replace water, salts and sugar. You can buy oral rehydration solutions from most supermarkets and pharmacies. Your pharmacist can recommend a rehydration solution that is right for you. Your GP or IBD team might give you a recipe to make your own ORS at home. Make sure you follow all instructions carefully.

The easiest way to avoid dehydration is to make sure that you drink enough. The EatWell Guide recommends drinking 6 to 8 glasses of fluids a day. This is around 1.2 litres in total, which equals 6 x 200ml glasses or 8 x 150ml glasses. Water and diluted squash are good choices to stay hydrated. When you are well hydrated, your pee should be a pale yellow colour.

You may need to drink more when there is a higher risk of becoming dehydrated. This could be when:

• The weather is very hot
• You are sweating due to exercise
• You have diarrhoea or are being sick (vomiting)

Do not wait until you feel thirsty before you start drinking extra water.

Drinking more water than your body can process can lead to hyponatremia. This is a rare but serious condition where the amount of salt (sodium) in your blood is abnormally low. If you feel uncomfortable or bloated from drinking, take a break from drinking and allow yourself time to recover.

If you have frequent diarrhoea, you may want to consider taking anti-diarrhoeal medicines. You should not take anti-diarrhoeal medicines if you are in a flare, if you have a high temperature, or if you have blood in your poo. You may not be able to take anti-diarrhoeal medicines if you have a narrowing in your bowel called a stricture. You should check with your doctor or IBD team before taking anti-diarrhoeal medicines.

If you have an ileostomy, food and drink pass through your small bowel and waste comes out through an opening in your tummy called a stoma. Food and drink do not pass through your large bowel, which is where water and salts are usually absorbed. It is important to drink enough water to keep yourself well hydrated. Your IBD team may recommend that you add extra salt to your meals (around a teaspoon a day).

Oral rehydration solutions (ORS) can be useful if you have short bowel syndrome or a high-output ileostomy. Your IBD team will let you know the best ORS for you. It is important that you follow instructions carefully. You may need to avoid drinking plain water while you are having an ORS.

If you have high or watery output from your stoma, your stoma nurse might recommend anti-diarrhoeal medicines, like loperamide, or thickening sachets to put in your bag.

Read more about eating and drinking with an ileostomy in our living with a stoma information.