Clive Coleman tells the story for BBC Radio 4 of the Carbolic Smoke Ball Company. It was an 1892 case of fraudulent advertising. The case against them is "seen by some as the birth of modern consumer protection":
The carbolic smoke ball was a peculiar device marketed as a cure for various ailments including influenza. It consisted of a rubber ball, filled with powdered carbolic acid. You squeezed the ball sending a puff of acidic smoke right up a tube inserted into your nose. The idea was that your nose would run and the cold would be flushed out.
The company making the ball advertised it in the Pall Mall Gazette offering a £100 reward to anyone using it correctly who then contracted influenza. They deposited £1,000 in the Alliance Bank in Regent Street to show the money was there.