When You're Sick

Being sick can make your blood glucose (sugar) level go up very high. It can also cause serious conditions that can put you in a coma.

The best way to prevent a minor illness from becoming a major problem is to work out a plan of action for sick days ahead of time. Then when you become sick, you will feel safe and secure. You will already know what to do and you will have the supplies onhand to do it.

What Happens When You're Sick

When you're sick, you're under stress. To deal with this stress, your body releases hormones that help it fight disease. But these hormones have side effects. They raise blood glucose levels and interfere with the blood glucose-lowering effects of insulin.

As a result, when you are sick, it is harder to keep your blood glucose in your target range. Ketoacidosis leading to a diabetic coma can develop, particularly in people with type 1 diabetes. People with type 2 diabetes, especially older people, can develop a similar condition called hyperosmolar hyperglycemic nonketotic coma. Both conditions are dangerous and can be life-threatening.

Making a Sick-Day Plan

Prepare a plan for sick days in advance. Work with your doctor, or a diabetes educator. The plan will include when to call your diabetes team, how often to measure blood glucose and urine ketones, what medications to take, and how to eat.

Also, attach to your plan a list of phone numbers for your doctor, diabetes educator, and dietitian. Make sure you also know how to reach them at night and on weekends and holidays. Then when illness strikes, you will be ready.

When to Call Your Diabetes Team

You do not need to call your team every time you have a sniffle. But you will probably want to call if certain things happen. For example:

  • you've been sick or have had a fever for a couple of days and aren't getting better
  • you've been vomiting or having diarrhea for more than 6 hours
  • you have moderate to large amounts of ketones in your urine
  • your glucose levels are higher than 240 even though you've taken the extra insulin your sick-day plan calls for
  • you take pills for your diabetes and your blood glucose level climbs to more than 240 before meals and stays there for more than 24 hours
  • you have symptoms that might signal ketoacidosis or dehydration or some other serious condition (for example, your chest hurts, you are having trouble breathing, your breath smells fruity, or your lips or tongue are dry and cracked)
  • you aren't certain what to do to take care of yourself

Be ready to tell what medications you've taken and how much, how long you've been sick, whether you can eat and keep food down, whether you've lost weight, and what your temperature, blood glucose level, and urine ketone level are. To be prepared, keep written records of all these things as soon as you become sick.

Keep Your Notebook Handy

No matter what kind of diabetes you have, measure your blood glucose and urine ketones more often than usual. If you have type 1 diabetes, you may need to measure blood glucose and urine ketones every four hours. Measuring ketones is very important because these waste products are more likely to build up when you are sick and lead to ketoacidosis.

If you have type 2 diabetes, checking blood glucose four times a day may be enough. You might only need to measure ketones if your blood glucose is higher than 300. If you do not have a meter, talk to your diabetes educator about getting one.

Diabetes Medications

When sick, you will still need to continue medications for your diabetes. Even if you are throwing up, don't stop your medications. You need them because your body makes extra glucose (sugar) when you are sick.

If you have type 1 diabetes, you may have to take extra insulin to bring down the higher blood glucose levels. If you have type 2 diabetes, you may be able to take your pills, or you may need to use insulin for a short time. In either case, work with your diabetes team to develop your sick-day plan.


Eating and drinking can be a big problem when you're sick. But it's important to stick to your normal meal plan if you can. In addition to your normal meals, drink lots of non-caloric liquids to keep from getting dehydrated. These are liquids like water and diet soft drinks. It's easy to run low on fluids when you are vomiting or have a fever or diarrhea. Extra fluids will also help get rid of the extra glucose (and possibly, ketones) in your blood.

But what if you can't stick to your normal meal plan? Your sick-day plan should contain a meal plan. Try to take in your normal number of calories by eating easy-on-the-stomach foods like regular (non-diet) gelatin, crackers, soups and applesauce.

If even these mild foods are too hard to eat, you may have to stick to drinking liquids that contain carbohydrates. Aim for 50 grams of carbohydrate every three to four hours. Your sick-day plan may include regular (not diet) soft drinks. Other high-carbohydrate liquids and almost-liquids are juice, frozen juice bars, sherbet, pudding, creamed soups and fruit-flavored yogurt. Broth is also a good choice.

To prepare for sick days, have onhand at home a small stock of non-diet soft drinks, broth, applesauce and regular gelatin.

Medications to Watch Out For

You may want to take extra medications when you are sick. For example, if you have a cold, you may want to take a cough medicine.

Always check the label of over-the-counter medicines before you buy them to see if they have sugar. Small doses of medicines with sugar are usually okay. But to be on the safe side, ask the pharmacist or your team about sugar-free medicines.

Many medications you take for short-term illnesses can affect your blood glucose levels, even if they don't contain sugar. For example, aspirin in large doses can lower blood glucose levels. Some antibiotics lower blood glucose levels in people with type 2 diabetes who take diabetes pills. Decongestants and some products for treating colds raise blood glucose levels.

If you must go to the emergency room or see a different doctor than usual, be sure to say you have diabetes, or have your identification bracelet in plain view. List all the medications that you are taking.

Your blood glucose level can also be affected by medications you take for chronic or long-term conditions.

See also: "Common Cold Remedies: Your guide to over-the-counter medications and diabetes care" by Erika Gebel, PhD, Diabetes Forecast, November 2012

  • Last Reviewed: July 12, 2013
  • Last Edited: June 5, 2015

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