A new government consultation asks whether the spot-ons and collars millions of owners rely on should be reclassified, amid mounting evidence that their active ingredients are turning up in rivers, fish, bird nests and coastal waters.

The monthly ritual is familiar to millions of owners: part the fur, squeeze the pipette, rub it in. Today, the Government has opened a UK-wide call for evidence asking whether the way those spot-ons are sold should change.

Launched jointly by the Veterinary Medicines Directorate (VMD), the Department for Environment, Food and Rural Affairs and Water Minister Emma Hardy MP, the eight-week consultation follows a run of research linking two active ingredients in particular – fipronil and imidacloprid – to chemical contamination in Britain’s rivers and streams.

Recent research funded by the VMD found that the application of certain flea and tick treatments by pet owners is contributing to these chemicals being detected in watercourses. Contamination is reaching rivers through wastewater pathways – owners washing their hands, bathing treated pets, laundering pet bedding – and directly, when treated dogs swim in lakes, ponds and rivers.

Monitoring by the Environment Agency has found concentrations in surface water that frequently exceed toxicity thresholds for aquatic insects. Residues have also been turned up in river sediments, fish tissue, wild bird nests and coastal waters, suggesting multiple pathways by which contamination may occur.

What ministers are proposing

The VMD is stopping short of a ban. Instead, it is asking whether fipronil- and imidacloprid-based products should be reclassified so they can no longer be picked up off a supermarket shelf or ordered freely online.

Under the option being examined, these medicines would only be available from vets, pharmacists, or Suitably Qualified Persons (SQPs) – trained professionals who can give point-of-sale advice to pet owners on correct use and disposal.

Water Minister Emma Hardy said:

“This Government is committed restoring nature and cleaning up our rivers.

“We are making progress on reducing the presence of forever chemicals in our waterways and this call for evidence is another important step.

“These treatments play a vital role in pet health and welfare, but it is right that we look at whether they should only be made available for sale via medical practitioners who can advise the public on their correct usage.”

VMD Chief Executive Officer Abigail Seager said:

“We know that fipronil and imidacloprid play an important role in protecting pets and people from parasites and the diseases they can carry. However, these substances are entering our waterways and may be having wider environmental impacts.

“As part of the call for evidence we want to hear as many perspectives as possible to ensure future decisions help us maintain appropriate availability of veterinary medicines on the UK market, while protecting animal health and the environment.”

Professor Jason Weeks, Chair of the Pharmaceuticals in the Environment Group, welcomed the move:

“I am pleased to see the VMD taking forward a distribution category review for these medicines. This work is fully in line with the cross-government Pharmaceuticals in the Environment roadmap and is an important step in ensuring that environmental concerns are considered in a timely and evidence led way. It is encouraging to see momentum building and real progress being made on this issue.”

It should however be noted that parasitic infections remain a significant risk to companion animals and, in certain instances, humans. Ready access to effective, regulated parasite control products plays a vital role in preventing disease, supporting animal welfare, and reducing the risk of zoonotic transmission.

Dawn Howard, Chief Executive of NOAH (National Office of Animal Health), said:

“Parasite control is a cornerstone of responsible pet ownership. While we support a thorough and transparent review, it is essential that decisions are grounded in sound science and a full understanding of the real-world impacts on animal health and welfare.

“Pet owners are already under financial pressure, and affordability directly influences whether animals receive the treatments they need. Any move that increases costs or reduces access risks leaving more animals unprotected.

“AVM-GSL products provide a convenient and effective route for pet owners to protect animals from parasites. Removing or restricting that access could create further barriers to timely treatment, particularly for those who are already unable to access veterinary services.”

Why now

The case for action has been building for several years. Both fipronil and imidacloprid are potent insecticides. Both were restricted for outdoor agricultural use in the EU over concerns about their persistence in the environment and harm to non-target insects, including bees and other pollinators. Yet they have remained widely available in spot-on pipettes, shampoos and impregnated collars for cats and dogs, on the assumption that pet-scale use wouldn’t reach the environment in damaging quantities.

Growing monitoring data has challenged that assumption. Environment Agency sampling has previously found fipronil in the vast majority of English river samples tested, often at concentrations exceeding safe thresholds for aquatic life. Residues have also turned up in the nests of songbirds – where they have been linked in separate research to higher rates of egg failure and chick mortality.

For the small invertebrates that underpin river food webs – the caddisflies, mayflies and midges that feed fish and birds – even low concentrations of these neurotoxic chemicals matter.

What the call for evidence is asking

The consultation is seeking views on two things.

First, the data itself: the science on environmental contamination, how serious it is, and where the remaining gaps lie.

Second, the practical consequences of any change. If fipronil and imidacloprid products were moved into a prescription-style supply route, what would that mean for animal welfare? For owners on tight budgets? For online retailers, subscription healthcare plans and independent pet shops? For access in rural areas, where a trip to the vet is not a short drive?

Animal welfare, the VMD stresses, remains paramount, and continued access to effective flea and tick treatments for pet owners is a key priority. A full ban on sale is not being considered.

The bigger picture

The call for evidence delivers on commitments made under the cross-government Pharmaceuticals in the Environment Roadmap launched last year. That roadmap set out key actions to address the levels of fipronil and imidacloprid entering UK waterways while protecting animal welfare – including commissioning research to better understand the issue and using the resulting evidence to support an international review of environmental risk assessment guidelines.

The consultation is UK-wide and will remain open for eight weeks.

For Britain’s 22 million or so cats and dogs and the people who love them, the question being asked is not whether to protect pets from parasites – it is how to do so without contaminating the rivers those same pets so happily splash in.