One day, he and his brother, John Keith Kellogg, left some wheat to cook while they ran some errands, and returned to find that the wheat had overcooked and gone stale. As they had a low budget, they decided that instead of discarding the mess, they would put go ahead and process it and see what happened. To their surprise, what came out was flakes, which they served to their patients. This on 8 August 1894, and a patent for "Flaked Cereals and Process of Preparing Same" was filed on 31 May 1895, and issued on 14 April 1896.
The product became very popular among the patients, and shortly afterward, the brothers began experimenting with other grains. They soon formed their own company to market their product, they originally named their company Battle Creek Toasted Corn Flake Company, which was later renamed Kellogg's.
The mascot of Kellogg's Corn Flakes is Cornelius "Corny" Rooster. In early adverts, his catchphrase would be, "Wake up, up, up to Kellogg's Cornflakes!", but later on he stopped talking and simply crowed.
One of the former patients of Dr. Kellogg was C. W. Post, who later went on to form a rival company for Kellogg's by selling the original Corn Flakes knockoff, Post Toasties.
