Carbolic Smoke Ball Co. was a company that manufactured and sold a product called the “Carbolic Smoke Ball,” which was claimed to prevent influenza and other diseases. The company published an advertisement stating that they would pay £100 to anyone who used the smoke ball as directed and still contracted influenza. The advertisement also stated that £1,000 had been deposited in a bank to show their sincerity.

Mrs. Carlill, a customer, purchased and used the smoke ball as instructed but still contracted influenza. She then claimed the £100 reward. However, the company refused to pay, arguing that:

1. The advertisement was not a serious contractual offer but mere “puffery.”
2. There was no formal acceptance or communication of acceptance.
3. There was no consideration from Mrs. Carlill.

Final Order (Judgment)

The Court of Appeal ruled in favor of Mrs. Carlill, holding that:

1. The advertisement was a unilateral offer, which could be accepted by anyone who performed the conditions stated.
2. Mrs. Carlill accepted the offer by using the smoke ball as directed, and no formal acceptance was necessary.
3. There was valid consideration, as the use of the smoke ball created inconvenience and benefit to the company (increased sales).
4. The promise was legally binding, especially since the company had deposited money in the bank to show sincerity.

Thus, Mrs. Carlill was entitled to the £100 reward, and this case became a landmark precedent in contract law, particularly for unilateral contracts.