The Carbolic Smoke Ball Company manufactured a rubber ball filled with carbolic acid powder, marketed as a preventative against influenza and other ailments. The company placed advertisements in newspapers across London promising to pay £100 to any person who purchased the smoke ball, used it as directed three times a day for two weeks, and still caught influenza afterward. To back up the promise and show the offer was serious rather than a marketing gimmick, the advertisement stated that the company had deposited £1,000 with the Alliance Bank specifically to meet any such claims.

Mrs. Louisa Carlill read the advertisement, bought a smoke ball from a chemist, and used it exactly as directed, three times daily, for nearly two months. Despite her diligence, she caught influenza. When she sought the promised £100, the Carbolic Smoke Ball Company refused to pay. The company argued the advertisement was not a genuine offer at all, but merely an exaggerated sales pitch, or "puff," that no reasonable person would take as a serious promise to pay. It also argued that even if it were an offer, Mrs. Carlill never communicated her acceptance before using the ball, and that an offer to the whole world could not be accepted by one person's unilateral performance.

Mrs. Carlill sued the Carbolic Smoke Ball Company to recover the promised £100. The trial court, presided over by Hawkins, J., found in her favor, holding that the advertisement constituted a binding offer that she had accepted by performance. The Carbolic Smoke Ball Company appealed the judgment to the Court of Appeal.

(Lindley, L.J.)

Yes. The advertisement was a genuine, binding offer to the world, and Mrs. Carlill accepted it by performing the conditions it specified, entitling her to the promised £100. An advertisement can be more than mere puffery if its language shows that the advertiser intended to be legally bound; here, the deposit of £1,000 with a named bank was strong evidence that the company meant business rather than merely engaging in vague sales talk. A unilateral offer made to the public at large, rather than to a specific individual, is nonetheless a valid offer, and it can be accepted by anyone who comes forward and performs the specified conditions, since the offeror is really only bound to the person or persons who actually fulfill the terms. Because this was a unilateral contract, formed through an act of performance rather than a reciprocal promise, notification of acceptance in advance was not required. Notice of acceptance exists to protect the offeror's interest in knowing whether a contract has been formed, but where the offer itself invites performance rather than a return promise, and where the nature of the transaction shows the offeror does not expect or need advance notice, performance of the condition is itself sufficient acceptance. There was also no shortage of consideration: the company received the benefit of increased sales of its smoke balls from members of the public who were induced to purchase and use the product by the promise of a reward, and Mrs. Carlill undertook the inconvenience of using the ball as directed for a substantial period in reliance on that promise.

### Majority (Lindley, L.J.)

Lindley, L.J. held that the £1,000 bank deposit was decisive evidence of a genuine intention to be bound, transforming what might otherwise be dismissed as puffery into a serious offer, and that performance of the stated conditions was sufficient acceptance without prior notice.

### Concurrence (Bowen, L.J.)

Bowen, L.J. reasoned separately that the nature of the offer, one made to the whole world and inviting performance of an act rather than a promise, implied a waiver of the ordinary requirement of communicated acceptance. In his view, the offeror who invites performance from anyone who wishes to accept must be taken to have dispensed with notice, since it would be commercially absurd to require every user of the smoke ball to first write to the company announcing an intent to use it.

### Concurrence (A.L. Smith, L.J.)

A.L. Smith, L.J. likewise concurred in the result, emphasizing that the advertisement was addressed to anyone who performed the condition, and that Mrs. Carlill had done precisely what was asked of her, using the smoke ball as directed and still contracting influenza, entitling her to enforce the promise.