How Do I Manage My Blood Sugar When I’m Sick?

Medically Reviewed by Michael Dansinger, MD on August 15, 2024
Written by WebMD Editorial Contributors
2 min read

When you have diabetes, sick days often mean more than a runny nose and sneezing. An illness like a cold, the flu, or any condition that makes you throw up or gives you diarrhea can also boost your blood sugar. So can an infection.

That means you have to stay on top of your blood sugar levels. Here are some guidelines:

  • Check your blood sugar every 4 hours.
  • Test for ketones if you have type 1 diabetes and your sugar level is above 240mg/dL -- or if your doctor tells you to. Ketones are a form of waste that people with type 1 make when they’re under stress (like an illness). Call the doctor if you find ketones in your urine. Depending on how sick you are, they may suggest you go to the emergency room.
  • Check your temperature regularly.
  • Drink liquids if you can’t keep solid food down. Have one cup of liquid every hour while you’re awake to prevent dehydration. If you can’t hold down liquids, you may need to go to the emergency room or hospital.
  • Don’t stop taking insulin, even if you can’t eat solid food. You may need to eat or drink something with sugar so that your blood sugar doesn't drop too low.
  • You may need to stop taking medicines by mouth for type 2 diabetes while you’re sick. Check with your doctor if you’re not sure what to do.
  • If you need an over-the-counter drug to control symptoms like cough and nasal congestion, ask your doctor or pharmacist for a list of sugar-free products.

Eat or drink 30 to 50 grams of carbohydrates every 3 to 4 hours. That will keep your body nourished, stop it from making ketones, and prevent your blood sugar from dropping too low.

If you’re having trouble eating, try bland foods like the ones listed below. Each equals one carbohydrate choice.

  • 1/2 cup regular gelatin
  • 1/2 cup regular soft drink, like 7-up or Sprite
  • 1/2 Popsicle
  • 1/2 cup unsweetened applesauce
  • 1/3 cup apple juice
  • 1/2 cup sports drink, like Gatorade

For additional liquids to stay hydrated, choose calorie-free liquids like water, diet soda, clear broth or bouillon.

Contact the doctor’s office if:

  • Your blood sugar stays higher than 180 mg/dL or lower than 70 mg/dL.
  • You can’t keep liquids or solids down.
  • You have a temperature over 101 F.
  • You have diarrhea or are vomiting.