Carlill v The Carbolic Smoke Ball Co Ltd (1893) is an English contract law case that dealt with the issue of offer and acceptance.

In this case, the Carbolic Smoke Ball Co Ltd advertised a product called the “smoke ball”, which they claimed could prevent users from getting influenza. The advertisement also stated that the company would pay £100 to anyone who contracted influenza after using the smoke ball as directed for a specified period.

Mrs. Carlill purchased and used the smoke ball as directed, but still contracted influenza. She then sued the company for breach of contract, claiming the £100 reward.

The company argued that the advertisement was not an offer, but rather a mere sales puff or a statement of intention. They also argued that Mrs. Carlill had not communicated her acceptance of the offer to them, as required for the formation of a contract.

The court held that the advertisement was an offer, and that Mrs. Carlill had accepted the offer by purchasing and using the smoke ball as directed. The court held that the requirement for communication of acceptance did not apply in this case, as the advertisement was a unilateral offer that could be accepted by performance.

The case of Carlill v The Carbolic Smoke Ball Co Ltd is an important case in the law of contract as it established the principle of unilateral offers and the acceptance of such offers by performance. The case also confirmed that advertisements can be offers if they contain sufficiently clear and specific terms, and that acceptance can be communicated by performance of the acts required by the offer.