Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.


Marketing communications for pest repellent equipment typically contain claims that the devices are highly effective at scaring unwanted animals, including rats, cats and moles, from homes and gardens. In recent years, the ASA, together with independent experts, has closely examined the evidence for claims for those devices, which can range from cat-shaped metal sheets with glowing eyes to ultrasonic and electromagnetic equipment. It has yet to accept any claim of efficacy. Marketers who do not hold evidence in the form of UK-based trials should not state or imply efficacy for the products, through either claims, visuals or product names. If the product name represents a claim of efficacy, for example “Rat-zap”, marketers should include a clear disclaimer that “Rat-zap has not been proven to repel rats” (See ‘Claims in names’).

No set rules exist for testing the efficacy of repellent devices under UK conditions. More than one experimental design could be acceptable. One such design consists of three phases: pre-treatment, treatment and post-treatment. The rationale is that the treatment effect is reversible and animal activity in the first and last stages should be similar (and obviously higher) than in the second stage. Each site where a device is tested should represent the environment in which the product is marketed for use and animal activity should be monitored closely throughout the trial period. Marketers who are looking to conduct trials are invited to submit their proposed research methodology to the Copy Advice team before proceeding.

Marketers should remember that customer testimonials do not by themselves constitute evidence of efficacy and claims, for example, that devices are harmless to pets or inaudible to humans, should be demonstrably true.

In 2003, the ASA upheld a complaint about an ad that claimed the advertiser's rodent pellets "killed rats without poison" and was "free from poisonous chemicals" (Natrocel Technologies Ltd, 28 May 2003).

See ‘Substantiation’ and ‘Testimonials’.


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