It is notable for its treatment of contract and of puffery in advertising, for its curious subject matter associated with medical quackery, and how the influential judges (particularly Lindley and Bowen) developed the law in inventive ways.

One CARBOLIC SMOKE BALL will last a family several months, making it the cheapest remedy in the world at the price—10s., post free.

Among the reasons given by the three judges were: (1) that the advertisement was not a unilateral invitation to treat to all the world, but rather an offer restricted to those who acted upon the terms set out in the advertisement; (2) that satisfying the stated conditions for using the smoke ball constituted acceptance of the offer; (3) that purchasing or merely using the smoke ball constituted good consideration, because it was a distinct detriment incurred at the behest of the company and, furthermore, more people buying smoke balls by relying on the advertisement was a clear benefit to Carbolic; and (4) that the company's claim that £1000 was deposited at the Alliance Bank showed the serious intention to be legally bound.

And fifth, the nature of Carlill's consideration (what she gave in return for the offer) was good, because there is both an advantage in additional sales in reaction to the advertisement and a "distinct inconvenience" that people go to when using a smoke ball.

The language is vague and uncertain in some respects, and particularly in this, that the £100 is to be paid to any person who contracts the increasing epidemic after having used the balls three times daily for two weeks.

It is for the defendants to shew what it does mean; and it strikes me that there are two, and possibly three, reasonable constructions to be put on this advertisement, any one of which will answer the purpose of the plaintiff.

Another meaning, and the one which I rather prefer, is that the reward is offered to any person who contracts the epidemic or other disease within a reasonable time after having used the smoke ball.

It appears to me, therefore, that the defendants must perform their promise, and, if they have been so unwary as to expose themselves to a great many actions, so much the worse for them.Bowen's opinion was more tightly structured in style, and is frequently cited[citation needed].

It was urged also, that if you look at this document you will find much vagueness as to the persons with whom the contract was intended to be made — that, in the first place, its terms are wide enough to include persons who may have used the smoke ball before the advertisement was issued; at all events, that it is an offer to the world in general, and, also, that it is unreasonable to suppose it to be a definite offer, because nobody in their senses would contract themselves out of the opportunity of checking the experiment which was going to be made at their own expense.

It is written in colloquial and popular language, and I think that it is equivalent to this: "£100 will be paid to any person who shall contract the increasing epidemic after having used the carbolic smoke ball three times daily for two weeks.”And it seems to me that the way in which the public would read it would be this, that if anybody, after the advertisement was published, used three times daily for two weeks the carbolic smoke ball, and then caught cold, he would be entitled to the reward.

My brother, the Lord Justice who preceded me, thinks that the contract would be sufficiently definite if you were to read it in the sense that the protection was to be warranted during a reasonable period after use.

Now, if that is the law, how are we to find out whether the person who makes the offer does intimate that notification of acceptance will not be necessary in order to constitute a binding bargain?

I will simply refer to Victors v Davies[10] and Serjeant Manning's note to Fisher v Pyne,[11] which everybody ought to read who wishes to embark in this controversy.

p. 47, which is cited and adopted by Tindal CJ, in the case of Laythoarp v Bryant,[12] is this: “Any act of the plaintiff from which the defendant derives a benefit or advantage, or any labour, detriment, or inconvenience sustained by the plaintiff, provided such act is performed or such inconvenience suffered by the plaintiff, with the consent, either express or implied, of the defendant.”Can it be said here that if the person who reads this advertisement applies thrice daily, for such time as may seem to him tolerable, the carbolic smoke ball to his nostrils for a whole fortnight, he is doing nothing at all — that it is a mere act which is not to count towards consideration to support a promise (for the law does not require us to measure the adequacy of the consideration).

If I say to a person, “If you use such and such a medicine for a week I will give you 5l.,” and he uses it, there is ample consideration for the promise.A L Smith's judgment was more general and concurred with both Lindley and Bowen's decisions.

is actually lodged at the bank where with to satisfy any possible demands which might be made in the event of the conditions contained therein being fulfilled and a person catching the epidemic so as to entitle him to the 100l.

Under the Consumer Protection from Unfair Trading Regulations[15] (secondary legislation, passed under the European Communities Act 1972), regulation 5 states that a commercial practice is misleading... "if it contains false information and is therefore untruthful... or if it or its overall presentation in any way deceives or is likely to deceive the average consumer... even if the information is factually correct"…in relation to a long list of actions and omissions by sellers.

Secondly, although it was not discussed in the case, there was evidence at the time that using the smoke ball actually made people more vulnerable to the flu (carbolic acid was put on the poisons register in 1900).

Thirdly, the Consumer Protection Act 1987 (which is also part of EU wide regulation under Directive 85/374/EEC[19]) creates a statutory tort of strict liability for defective products that cause any kind of personal injury or death, or damage over £100.

Similar regimes for product liability have developed around the world through statute and tort law since the early twentieth century, one of the leading cases being Donoghue v Stevenson.

"The amusing circumstances of the case should not obscure the surprising extent to which the court was prepared to conceive social relations in terms of contracts.

The law of contract is used by the court as an instrument for discouraging misleading and extravagant claims in advertising and for deterring the marketing of unproven, and perhaps dangerous pharmaceuticals...

The generality and abstraction of the rules permit both the extensive utilization of [contract law] and its application to the case, without any discussion of such matters as the moral claims of the parties, the nature of the market for pharmaceuticals and the problems generated by misleading advertising... Its doctrinal integrity helps to achieve legitimacy, because the law can be presented as objective and neutral, not a matter of politics or preference, but a settled body of rules and principles, legitimated by tradition and routine observance, and applied impartially and fairly to all citizens.

"[20]Professor A. W. B. Simpson, in an article entitled 'Quackery and Contract Law'[21] gave the background of the case as part of the scare arising from the Russian influenza pandemic of 1889-90.

After it was patented, the Carbolic Smoke Ball had in fact become rather popular in many esteemed circles including the Bishop of London who found it "has helped me greatly".

The Pharmaceutical Society of Great Britain had been fighting an ongoing battle against quack remedies, and had wanted specifically to get carbolic acid on the poisons register since 1882.

Furthermore, the Carbolic Smoke Ball Company had had no chance to check the validity of claims, of which there could be an indefinite number; much was made of this point in the argument.

"In a much more recent American case from the Southern District of New York, Leonard v Pepsico, Inc,[23] judge Kimba Wood wrote, "Long a staple of law school curricula, Carbolic Smoke Ball owes its fame not merely to "the comic and slightly mysterious object involved" ... but also to its role in developing the law of unilateral offers.

He described the culpable advert, and then said, "Many thousand Carbolic Smoke Balls were sold on these advertisements, but only three people claimed the reward of £100, thus proving conclusively that this invaluable remedy will prevent and cure the above mentioned diseases.

Simpson suggests that the new management "had failed to grasp the fact that vigorous advertising was essential to success in the field of quack medicine."