Oral glucocorticoids, a type of steroid, are often prescribed to treat asthma, rheumatoid arthritis, and irritable bowel syndrome. But while they help these health conditions, they can also lead to type 2 diabetes. The drugs mimic the effect of the hormone cortisol, which influences sugar metabolism and increases blood glucose levels. Experts say that glucocorticoids should only be used when asthma can’t be controlled by other measures, and that patients taking steroids should be alert to diabetes symptoms like increased thirst, frequent urination, and blurry vision.