Counterfeit flea treatment nearly kills pet cat, owners and regulators warn

A Persian cat in England was left gravely ill and required emergency intestinal surgery after its owner applied a counterfeit flea treatment purchased online, veterinary staff and the pet’s owner said.

Alan Wall said he bought what he believed was the same Frontline product he had used for years to protect his cat, Smokey. Within hours of application the cat began violently vomiting, refused food and water and became lethargic; a scan at a veterinary clinic revealed a blockage in Smokey’s intestines and emergency surgery was performed to save the animal’s life.

Veterinarians later identified exposure to pirimiphos-methyl, an organophosphate insecticide that is highly toxic to cats, according to Dr. Heilin-Anne Leonard-Pugh. She said the chemical can prevent the body from breaking down acetylcholine, causing overstimulation of the nervous system and symptoms including vomiting, uncoordinated gait, muscle tremors, weakness, paralysis, difficulty breathing, restlessness, urinary incontinence, a low heart rate and seizures. In severe cases, she said, death can occur.

"Watching him suffer, not knowing whether he would pull through, was heartbreaking. It’s taken a huge emotional toll on all of us," Wall said. He said he has paid roughly £3,000 in surgery and follow-up veterinary care.

Officials from the Intellectual Property Office (IPO) and the Veterinary Medicines Directorate (VMD) said counterfeit pet treatments sometimes contain harmful substances and can lack the appropriate active ingredients or safe formulation of genuine veterinary medicines. The agencies urged pet owners to be cautious when buying animal health products online, particularly from sellers offering heavy discounts or flash sales, or when packaging appears flimsy, damaged or contains spelling and grammar errors.

The IPO and VMD advised consumers to look for missing information such as leaflets or expiry dates, instructions not provided in English, unusual smells, colours or textures, and poor-quality tablets, capsules, vials or pipettes that appear homemade. They also said sellers requesting payment by bank transfer or asking for unnecessary personal information should be treated with suspicion.

New counterfeit-goods research (Wave 4) cited by the IPO found that global e-commerce sites are common channels for counterfeit purchases and that in 2024 nearly one in five consumers (17%) unknowingly purchased goods later found to be fake. Last year the agencies issued 122 seizure notices for unauthorised animal medicines and supplements, preventing about 18,000 illegal items from reaching consumers.

"We are a nation of animal lovers, and criminals dealing in counterfeits are targeting pet owners with complete disregard for the animal’s wellbeing," said Helen Barnham, deputy director of enforcement at the IPO. "This can have some distressing consequences, as they may contain toxic chemicals that are harmful to our pets. We are urging pet owners to be vigilant when purchasing any type of animal treatment, and beware of any offers that ‘look too good to be true’." She added that suspected counterfeit goods should be reported to local Trading Standards or Crimestoppers Online.

Caroline Allen, chief veterinary officer at the RSPCA, said her organisation is "very concerned about counterfeit vet treatments on sale which can be highly toxic to pets" and reiterated advice to seek professional veterinary care if owners have any health concerns. She acknowledged that financial pressures can drive owners to seek cheaper treatments online but warned that cheaper alternatives may put animals at serious risk.

Veterinarians recommend that owners who suspect their pet has been exposed to a counterfeit medicine seek veterinary attention immediately. Clinicians can assess symptoms, perform diagnostic imaging or tests, and provide treatments such as decontamination, supportive care and, when necessary, surgery. Regulatory bodies continue to monitor and seize unauthorised products and advise consumers to report suspect listings to help prevent further harm.