Dietary supplements are vitamins, minerals, herbs and other substances meant to improve your diet. They can come as pills, capsules, powders and liquids. Supplements do not have to go through the testing that drugs do. Some supplements can play an important role in health. For example, pregnant women can take the vitamin folic acid to prevent certain birth defects in their babies. Taking supplements can also be a type of complementary or alternative medicine (CAM). To take a supplement as safely as possible Tell your doctor about any dietary supplements you use Do not take a bigger dose than the label recommends Stop taking it if you have side effects Read trustworthy information about the supplement