Post's poor health found him seeking treatment, and hearing of the many success stories that came out of Battle Creek, a frail Post found himself at the doors of Kellogg's Sanitarium. Unfortunately, Kellogg's many "cures" failed for Post. The daily enemas, light baths, and diet changes did little to aid Post, whose continuously declining health led Kellogg to gravely inform Post's wife, Ella, that he was certain to die. Kellogg's bleakness in his prognosis combined with the astronomical rates that Kellogg charged for his services and the depletion of the family's available funds led Post's wife to promptly wheel him out of the Sanitarium .
Ella Post took C.W. to a woman named Elizabeth Gregory, who was a close follower of Christian Science and Mary Baker Eddy. Upon C.W.'s arrival to her home, she began to minister to Post in the Christian Scientist style. Miraculously, Post's health began to return that very night. He woke up the next morning, ate a large breakfast, and marked the event with the saying "I am well!". Two years later, in 1893, he wrote a book titled "I Am Well!" The Modern Practice of Natural Suggestion as Distinct from Hypnotic and Unnatural Influence. Post decided also decided to open a sanitarium to rival Kellogg's: it would provide similar care, but with more focus on positive thinking, and would also be much, much cheaper than Kellogg's resort. Post called it La Vita Inn but unlike Kellogg, Post looked to improve his patients' health with more positive thought, and served more meat than Kellogg did at his resort.
Post especially liked one food served at Kellogg's sanitarium, a beverage known as "caramel coffee", a cereal based coffee substitute consisting of roasted wheat and molasses. Before Post had opened his own sanitarium, he had offered to commercially market the beverage for Kellogg, an offer Kellogg refused. Post then began to devise his own version of the beverage, hiring a Swiss chemist to design the recipe. Post sank large amounts of money into the effort, and was completely dissatisfied with the results, so he decided to find the recipe himself, an effort that bought him success. He called the beverage "Postum", and began to sell it commercially in 1895 through the Postum Cereal Coffee Company. Post's fledgling cereal business was about to explode. Post began to heavily market Postum and began to sell vast quantities of the product. His advertisements claimed that the drink would build strength and be easier on the system- one ad simply stated "If Coffee Don't Agree, Use Postum".
Postum was a success, and Post looked to follow that success with another coffee substitute. He created Grape Nuts in 1898 as such an item. The mysterious name for the cereal, which contains neither grapes nor nuts, came from its ingredients and its taste: Maltose, which Post called "grape sugar", and the nutty flavor of the cereal. Unfortunately, Grape Nuts didn't sell well- until Post decided to sell it as a cold breakfast food instead. Post marketed Grape Nuts with the same intensity as he had Postum, and marketed it heavily as a brain food, claiming it made the brains and nerves healthy. Grape Nuts became immensely popular and bought Post immense wealth.
Unfortunately, the breakfast cereal market, new and exciting as it was, was rife with imitators. Exactly like the Kellogg brothers, Post found his products imitated by other other companies. In the case of his signature drink Postum, Post created an imitation brand himself. He called it Monk's Brew, and sold it for a fraction of the cost of Postum, driving his competitors out of business. Post wasn't above imitating other companies either though. Post created Elijah's Manna, an imitation of Kellogg's corn flakes. The box featured a picture of the Biblical Elijah being fed by a raven. The product infuriated the churchgoing public, who insisted that Post cease taking Elijah's name in vain. Post soon changed the cereal to Post Toasties.
Eventually, the marketing efforts of the cereal companies, especially Post's, grew too incredible in their claims. Grape Nuts, which had also been marketed as a way to keep a person's body temperature down when it got too high and easy on the body to digest, was marketed as a cure for appendicitis: Ads for the cereal recommended consuming large amounts of the product to flush out the intestines, which would cure the ailment. Advertisements also recommended the regular consumption of the cereal as a preventative measure.
In 1911, Collier's Weekly, the renowned muckraking publication, refused to run any ads for Post's company on the grounds that as a result of the Pure Food and Drug Act of 1906, they would no longer publish any ads for medicine or products that purported themselves to have a medicinal effect. The magazine also reportedly allowed the editor to refuse any advertisements that he thought made extravagant and unreasonable claims. Collier's later published an editorial stating (quite correctly) that the implication that Grape Nuts could ward off appendicitis was not only false, but potentially deadly. The feud between the Postum company and Collier's Weekly that followed was extremely hostile and bitter. Post began to ran advertisements smearing the publication, indicating that the reason his advertisements were removed from the magazine and the editorial claiming that the editorial claiming the consumption of Grape Nuts during a bought of appendicitis had potentially deadly consequences was that he refused to pay extra advertising money to Collier's. Essentially, he was accusing Collier's Weekly of blackmail and spent 150,000 dollars on the campaign. The advertisement, sporting the headline "The Yell-Oh Man and One of His Ways" outlined Post's claims against Collier's. Post was soon sued for libel, in a court case that became long and bitter as Collier's attacked Post and his company for their false claims. The magazine especially pressed Post on the use of his testimonials in advertisements, which he claimed in court were unsolicited. As it turned out though, Post had solicited his testimonials, offering money for stories from people who claimed to be healed of ailments by consuming Post's products. What's more, none of the testimonials were investigated for truthfulness before being placed in advertisements, and none of the testimonials published in the advertisements were published as is- they had all been rewritten prior to their publishing. Post lost the libel suit, and Collier's was awarded 50,000 dollars, a then unprecedented amount. Unfortunately, Post would not live very long after the court decision. In 1913 his health declined sharply, and he sank into a deep depression and on May 9, 1914, Charles William Post committed suicide with a gunshot to the head. He was 59 years old and left an enormous fortune to his daughter, who inherited the company. The vast Post fortune had been built on only four products: Postum, Instant Postum, Post Toasties, and Grape Nuts. The fact that Post was able to amass such wealth on such a limited range was a true testament to his advertising prowess.