Despite the overwhelming choices at your local drugstore, most over-the-counter painkillers rely on just one of four active ingredients.

Acetaminophen (in Tylenol) relieves pain by raising your overall pain threshold. It decreases fever by getting rid of the body’s excess heat.

Aspirin, ibuprofen (in Motrin), and naproxen sodium (in Aleve) are all non-steroidal anti-inflammatory drugs that block your body’s production of pain- and inflammation-causing substances called prostaglandins, which also affect your body’s temperature.

Which pain medication to take depends on your age, medical history, and underlying conditions such as pregnancy. Talk to your doctor about which one is right for you.