Crestor is a collection of drugs called HMG CoA reductase inhibitors, or "statins." Crestor reduce levels of "bad" cholesterol and triglycerides in the blood, while rising levels of "good" cholesterol. Crestor is used to lesser cholesterol and triglycerides in the blood. Crestor is also used to lower the risk of stroke, heart attack, and other heart difficulty in people with diabetes, coronary heart disease, or more risk factors. Crestor is used in adults and kids who are at least 10 years old.