100% natural. For tastier grilling it has to be Heinz. Estd. 1869. Made with 100% natural ingredients, including finely milled mustard seeds and a secret blend of spices and vinegar, for the perfect balance of flavor and tang. Heinz, uncommon quality since 1869. - H.J. Heinz. Questions or comments? Call 1-800-255-5750. Visit Us at: www.heinz.com.