Customer reviews and testimonials are perhaps one of the most effective advertising tools in online retail. After all, recommendations from other customers often seem more credible to consumers than a company’s own advertising.
This very credibility has a flip side: anyone who wants to benefit from the particular persuasive power of statements by others must also take responsibility for their content.
The Hanseatic Higher Regional Court (OLG) of Hamburg has set a clear limit to this practice: anyone who uses statements by others as an advertising tool themselves is directly liable, as the perpetrator, for this advertising conduct of their own (direct liability, or Täterhaftung). In the case decided, it was particularly problematic that individual positive experiences gave the impression that the successes described were to be expected generally (OLG Hamburg, order of 15 July 2026 – 3 W 33/26). The advertiser can then no longer fall back on the objection that the statements came merely from customers or third parties.
What Was the Case About?
A manufacturer advertised a prescription-only veterinary medicinal product to veterinarians with a collection of eleven quoted user statements, including statements about a “better effect than other products”, an “unreserved” recommendation or the “full satisfaction” of the animal keepers.
In fact, the quoted statements concerned the efficacy of the medicinal product, specific treatment successes and, in part, its superiority over other products. Through their incorporation into the advertising, individual positive experiences could give the impression that the successes described were to be expected generally. Where superiority over other products was claimed, moreover, the corresponding scientific head-to-head comparisons were lacking.
A competitor challenged all eleven of these statements. It considered the claims of efficacy, success and superiority contained in them to be misleading and not adequately backed up scientifically.
After the applicant had been unsuccessful before the Regional Court with regard to these statements, the OLG Hamburg partially amended the decision on the applicant’s immediate appeal and prohibited all eleven statements. The Senate set the amount in dispute for the appeal proceedings at EUR 160,000.
What the Senate regarded as problematic was not the mere use of testimonials as such, but the impression conveyed by their promotional presentation. Through their incorporation into the advertising, individual positive experiences from the testimonials could give the impression that the successes described were to be expected generally. The recipient of the advertising could therefore understand the personal experience reports as a statement about the general efficacy of the product. For such a generalisation, however, the corresponding scientific substantiation was lacking.
The OLG Hamburg found the advertising misleading under Art. 119 para. 5 of Regulation (EU) 2019/6 because individual positive experiences, through their promotional presentation, gave the impression that the treatment successes described were not merely isolated cases but were to be expected generally or regularly.
Whoever Quotes Is Doing Their Own Advertising – and Whoever Advertises Is Liable Themselves
The fact that these were genuine positive experience reports from veterinarians did not exonerate the manufacturer. Instead, the OLG proceeded on the basis that this was the manufacturer’s own advertising.
The manufacturer had itself incorporated the statements without comment into its advertising for the veterinary medicinal product.
According to the OLG, what was decisive was not who originally formulated the sentences but who subsequently uses them as an advertising tool for the product. If the trader itself carries out the relevant commercial practice, it is directly liable for it as the perpetrator, according to the OLG.
The respondent had itself incorporated the veterinarians’ statements into its own advertising. Advertising with the veterinarians’ statements was therefore its own conduct. Hence, no additional attribution of the statements by way of the legal concept of “adoption as one’s own” was required.
Adoption as One’s Own – When a Third Party’s Statement Must First Be Attributed
Adoption as one’s own becomes relevant, by contrast, where a statement by a third party has not already been made the subject of an advertising act of its own by the person concerned, and the question therefore arises first whether the third party’s statement can nevertheless be legally attributed to that person.
That was the situation in the case “Customer Reviews on Amazon” decided by the Federal Court of Justice (BGH) (BGH, judgment of 20 February 2020 – I ZR 193/18): there, customers had submitted their reviews independently. These appeared next to the respective product offer by virtue of the review system provided by Amazon, without the seller having selected them itself or deliberately used them as its own advertising. That is why the question arose there in the first place whether the third-party customer statements could nevertheless be attributed to the seller as its own because it had adopted them as its own.
The decisive difference therefore lies not in the origin of the statement – in both cases it comes from third parties – but in who carries out the specific advertising act: if the trader itself actively makes a third party’s statement the subject of its advertising, it is directly liable for this advertising conduct of its own. If, on the other hand, the statement merely appears in its environment as a result of a third party’s actions, it must first be examined whether it can be attributed to the trader under the principles of “adoption as one’s own”.
Anyone who uses a statement by others as an advertising tool themselves therefore cannot defend themselves by arguing that the wording originally came from a customer, veterinarian or other third party.
When Does a Third Party’s Statement Become Your Own Advertising?
Whether a statement by a third party becomes an advertising measure of the company’s own therefore depends on its specific use. This is indicated in particular where the company selects the statement itself and deliberately uses it on its website, in advertisements, newsletters, testimonials or other advertising materials. The position may be different for automatically embedded reviews or platform content, over whose selection and presentation the company has no, or only limited, influence.
The question of whether information must be provided on the authenticity of such reviews is separate from responsibility for their content – on this, see “Why the Label ‘Google Review’ Alone Does Not Protect Against a Cease-and-Desist Letter”.
Own Advertising – and Then Misleading as Well
It was not the use of testimonials as such that was misleading. What was decisive, rather, was the impression the statements conveyed through their incorporation into the advertising.
The manufacturer used the positive experiences of veterinarians as an advertising tool without comment.
According to the OLG, the professional audience addressed therefore did not understand these statements merely as personal experiences from an individual practice. Rather, the quotations gave the impression that the treatment successes described were to be expected generally, beyond the individual case in question.
From statements such as “In my practice, the product worked very well”, the relevant audience understood the far more extensive message “Such treatment successes can generally be expected with this medicinal product.” – and did so in particular because of the way the statements were presented in the advertising.
In addition, some testimonials were not limited to personal experiences but asserted specific effects and even better efficacy compared with other products. For such objectively verifiable statements, the scientific evidence was lacking in the view of the OLG.
Strict Standard of Review for Medicinal Products
Under Art. 119 para. 5 of Regulation (EU) 2019/6, advertising for veterinary medicinal products must not contain any information that could be misleading or lead to incorrect use. The OLG also proceeds on the basis that the strictness principle of medicinal products advertising law continues to apply when assessing whether advertising is misleading. High standards therefore apply to the factual and scientific substantiation of claims of efficacy and superiority.
What is decisive here is the overall impression the advertising creates among the audience addressed. In the specific case, these were veterinarians. In the view of the OLG, they understood the embedded experience reports not merely as subjective individual experiences but, in part, as statements capable of generalisation about the efficacy of the veterinary medicinal product advertised and its superiority over other treatment options.
How the Statements Were Understood
In the eleven statements complained of, the misleading effect took different forms: individual positive experiences were generalised into general expectations of efficacy, claimed advantages over other treatments were not supported by the required head-to-head comparisons, and particularly far-reaching promises of efficacy went beyond what the available scientific data actually supported.
Particularly high requirements apply to claims of superiority. Where the impression is conveyed that one medicinal product is superior to another in its efficacy, the OLG requires a scientific direct comparison, that is, a so-called head-to-head study. Studies that merely compare the company’s own preparation with a placebo cannot prove superiority over a competing product.
These special scientific requirements for the advertising of veterinary medicinal products cannot simply be transferred to every instance of advertising with customer reviews. What is more generally transferable, by contrast, is the principle that a company must answer for statements by others if it uses them itself as an advertising tool.
When Statements by Others Become Your Own Advertising
For companies, the decision therefore means two things: anyone who deliberately takes statements by others into their own advertising bears responsibility for that advertising measure themselves. At the same time, it does not depend solely on whether the quotation used is “genuine”. What is decisive is what message the quotation conveys in the specific advertising context – and whether that very message is legally permissible and, where required, adequately substantiated.
