Diabetes - when you are sick

When you are sick, insulin does not work as well in your cells and your blood sugar level can be higher. This can happen even if you are taking the normal doses of your medicines, including insulin.

When you are sick, keep a close watch on diabetes warning signs. These are:

• High blood sugar that will not come down with treatment
• Nausea and vomiting
• Low blood sugar that will not rise after you eat
• Confusion or changes in how you normally behave

If you have any of these warning signs and cannot treat them yourself, contact your health care provider right away. Make sure your family members also know the warning signs.

Discuss with your provider, before you are sick, how best to handle illnesses. Typical sick day plans are below.

Check your blood sugar more often than usual (every 2 to 4 hours). Try to keep your blood sugar at less than 200 milligrams per deciliter (mg/dL) or 11.1 millimoles per liter (mmol/L). There may be times when you need to check your blood sugar every hour. Write down or record all your blood sugar levels, the time of each test, and the medicines you have taken.

If you have type 1 diabetes, check your urine ketones often, every time you urinate, if your blood sugar is high.

Eat small meals often. Even if you are not eating as much, your blood sugar can still get very high. If you use insulin, you may even need extra insulin injections or higher doses.

Do not do vigorous exercise when you are sick.

If you take insulin, you should also have a glucagon emergency treatment kit prescribed by your provider. Always have this kit available.

Drink plenty of sugar-free fluids to keep your body from getting dried out (dehydrated). Drink at least twelve 8-ounce (oz) cups or about 3 liters (L) of fluid a day.

Feeling sick often makes you not want to eat or drink, which, surprisingly, can lead to a higher blood sugar.

Fluids you can drink if you are dehydrated include:

• Water
• Club soda
• Diet soda (caffeine-free)
• Tomato juice
• Chicken broth

If your blood sugar is less than 100 mg/dL (5.5 mmol/L) or falling quickly, it is OK to drink fluids that have sugar in them. Try to check their effect on your blood sugar in the same way you check how other foods affect your blood sugar.

Fluids you can drink if your blood sugar is low include:

• Apple juice
• Orange juice
• Grapefruit juice
• Sports drink
• Tea with honey
• Lemon-lime drinks
• Ginger ale

Follow the “Rule of 15” when your blood sugar is below 70 mg/dL:

• You should have 15 grams (g) of fast-acting carbs, such as a tablespoon of sugar or honey, 3 to 4 glucose tablets, or a half cup of juice.
• Wait for 15 minutes and then check your blood sugar again.
• If your blood sugar level is still less than 70 mg/dL, repeat the steps until your blood sugar level reaches normal.

When you have an upset stomach, try to eat small meals. Try carbohydrates, such as:

• Bagels or bread
• Cooked cereal
• Mashed potatoes
• Noodle or rice soup
• Saltines
• Fruit-flavored gelatin
• Graham crackers

Many foods have the right amount of carbohydrates (about 15 g) for your sick-day diet. Remember, on sick days it is OK to eat some foods you might not normally eat, if you cannot eat your regular foods. Always check the label of foods to be sure you know their carbohydrate content. Some foods to try are:

• One half cup or 120 milliliters (mL) apple juice
• One half cup (120 mL) regular soft drink (non-diet, caffeine free)
• One fruit-flavored frozen pop (1 stick)
• Five small hard candies
• One slice of dry toast
• One half cup (120 mL) cooked cereal
• Six saltine crackers
• One half cup (120 mL) frozen yogurt
• One cup (240 mL) sports drink
• One half cup (120 mL) regular ice cream (if you are not throwing up)
• One quarter cup (60 mL) sherbet
• One quarter cup (60 mL) regular pudding (if you are not throwing up)
• One half cup (120 mL) regular fruit-flavored gelatin
• One cup (240 mL) yogurt (not frozen), sugar-free or plain
• Milkshake made with one half cup (120 mL) low-fat milk and one quarter cup (60 mL) ice cream mixed in a blender (if you are not throwing up)

When you are sick, you should try to eat the same amount of carbohydrates that you normally do. If possible, follow your regular diet. If you are having a hard time swallowing, eat soft foods.

If you have already taken your insulin and are sick to your stomach, drink enough liquids with the same amount of carbohydrates that you would normally eat. If you cannot keep food or liquids down, go to the emergency room for treatment. You will receive intravenous (IV) fluids.

If you have a cold or fever, use your sick day plan or contact your provider.

Most of the time, you should take all of your medicines as you usually do. Do not skip or double up on any medicine unless your provider tells you to.

If you cannot eat your normal amount of carbohydrates, use your sick day plan or contact your provider. You may need to make a change in your insulin dose or in the dose of your diabetes pills or other injections. You may also need to do this if your illness is making your blood sugar higher than normal.

Being sick increases the risk of more serious emergencies seen with diabetes.

Contact your provider if you have:

• Blood sugar higher than 240 mg/dL (13.3 mmol/L) for more than 1 day
• Moderate-to-large ketones with your urine tests
• Vomiting or diarrhea for more than 4 hours
• Any severe pain or chest pain
• A fever of 100°F (37.7°C) or higher
• Trouble moving your arms or legs
• Vision, speech, or balance problems
• Confusion or new memory problems

If your provider does not contact you back right away, you may need to go to the emergency room. This is particularly important if you are vomiting or have diarrhea for more than 4 hours.

Sick-day management - diabetes; Diabetes - sick day management; Insulin resistance - sick day management; Ketoacidosis - sick day management; Hyperglycemic hyperosmolar syndrome - sick day management

American Diabetes Association Professional Practice Committee for Diabetes. 4. Comprehensive medical evaluation and assessment of comorbidities: Standards of Care in Diabetes-2026. Diabetes Care. 2026;49(Supplement_1):S61-S88. PMID: 41358897 pubmed.ncbi.nlm.nih.gov/41358897/.

Centers for Disease Control and Prevention website. Diabetes: managing sick days. www.cdc.gov/diabetes/living-with/managing-sick-days.html. Updated May 15, 2024. Accessed July 7, 2026.

Dhatariya KK, Umpierrez GE, Crandall JP. Diabetes mellitus. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 210.

Gillard P, Atkinson MA, Mathieu C. Type 1 diabetes mellitus. In: Melmed S, Auchus RJ, Goldfine AB, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 35.

Updated by: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.