Insulin aspart is used to treat type 1 diabetes (condition in which the body does not produce insulin and therefore cannot control the amount of sugar in the blood) in adults and children. It is also used to treat people with type 2 diabetes (condition in which the body does not use insulin normally and therefore cannot control the amount of sugar in the blood) who need insulin to control their diabetes. In patients with type 1 diabetes, insulin aspart is usually used with another type of insulin, unless it is used in an external insulin pump. In patients with type 2 diabetes, insulin aspart also may be used with another type of insulin or with oral medication(s) for diabetes. Insulin aspart is a short-acting, manmade version of human insulin. Insulin aspart works by replacing the insulin that is normally produced by the body and by helping move sugar from the blood into other body tissues where it is used for energy. It also stops the liver from producing more sugar. Over time, people who have diabetes and high blood sugar can develop serious or life-threatening complications, including heart disease, stroke, kidney problems, nerve damage, and eye problems. Using medication(s), making lifestyle changes (e.g., diet, exercise, quitting smoking), and regularly checking your blood sugar may help to manage your diabetes and improve your health. This therapy may also decrease your chances of having a heart attack, stroke, or other diabetes-related complications such as kidney failure, nerve damage (numb, cold legs or feet; decreased sexual ability in men and women), eye problems, including changes or loss of vision, or gum disease. Your doctor and other healthcare providers will talk to you about the best way to manage your diabetes.