Red Dye No. 40, also known as Allura Red AC, is a synthetic food coloring commonly used in various food products, beverages, and cosmetics. It is derived from petroleum and is known for its bright red hue. This dye is approved for use in many countries, including the United States, where it is regulated by the Food and Drug Administration (FDA). While Red Dye No. 40 is widely used, some people may have sensitivities or allergic reactions to it. Research on its safety has produced mixed results, leading to ongoing discussions about its potential effects on health, particularly in children.