Type 2 diabetes mellitus is a common disease that interferes with the body's ability to store energy from food. The pancreas makes insulin, a substance that helps to store energy from food. People with type 2 diabetes make insulin but can't use it properly. The result is high blood sugar levels. Over time, high blood sugar can lead to blindness, kidney failure, nerve damage, and heart disease. Fortunately, keeping blood sugar under control can prevent complications. Although some people with type 2 diabetes can control their blood sugar with diet and exercise, drug treatment is often necessary. Some diabetes drugs are pills, but often these pills are not enough. These patients must take insulin injections (either alone or with pills) to control blood sugar levels. There are several types of insulin. Short-acting insulins begin to act soon after injection. Long-acting insulins do not begin to act for several hours and then continue to act for hours. Most long-acting insulins “peak,” meaning that they work most strongly to lower blood sugar at a certain time after injection. During this peak, a person can develop dangerously low blood sugar levels (hypoglycemia) unless enough food is available. Hypoglycemia is particularly dangerous during sleep because patients may not know that their blood sugar is low and that they need to eat. Insulin glargine is the newest long-acting insulin. Glargine is different from other long-acting insulins because it does not peak. Glargine works to lower blood sugar a little at a time over 24 hours. The best way to use glargine in type 2 diabetes is unknown.