• The Food Standards Agency (FSA) are warning pet owners not to feed dogs specific chews from China.

• Reports from the EU warn of a possible link to ‘werewolf syndrome’, which can cause serious behavioural changes. 

• Vets are also being asked to be alert to symptoms.

Dog owners have been warned by the Food Standards Agency (FSA) not to feed their pets specific dog chews from China.

The warning follows concerns from the European Union (EU), of the chews having a possible link to serious behaviour changes in dogs. With reports suggesting that these products are potentially linked to dogs experiencing what is known as ‘werewolf syndrome’.

There is no confirmed distribution of the chews to the UK and no cases have been detected in the UK so far. Tina Potter, Head of Incidents, Food Standards Agency said: “While there is no confirmed distribution of affected products to the UK, there is the possibility that some consumers may have purchased these online from international sellers.

“No unsafe dog chews have been identified but, based on international investigations so far, we are advising dog owners to avoid feeding the affected chews to dogs as a precaution. There is no evidence to suggest these products present any risk to human health.”

Dog owners are advised by the FSA not to feed the following treats to their pets:

Barkoo kaustange natur 29 cm

Packaging: bags of 570 grams (with 3 chewing bones) 

Code on packaging: 1148655 MHD 04.2027 3200PF027 

Barcode: 4260077047292

Barkoo kauknochen, geknotet natur 11cm 

Packaging: bags of 150 grams (with 3 chewing bones) 

Code on packaging: 1148592 MHD 07.2027 3200PF027 

Barcode: 4260077046875 

Barkoo Kauknochen geknotet 24cm 

Packaging: bags of 150 grams (with 3 chewing bones) 

Barcode: 4260077046899 

Code on packaging: 1148657 MHD05.2027 3200PF027

Barkoo Kauknochen geknotet mit Spirulina 12cm

Packaging: bags of 180 grams (with 3 chewing bones) 

Barcode: 4260077047261 

Code on packaging: 1148654 MHD 06.2027 3200PF027 

Chrisco Products: 

Chrisco Tyggeruller med kylling, 10 stk  

Item number: 12457 

EAN code: 5764630124578 

Use by dates: all dates 

Chrisco Tyggeruller med kylling & kyllingelever, 100g

Product no. 12324 

EAN code: 5764630123243 

Use by dates: 01/12/2025; 05-01-2026; 15-03-2026; 18-03-2026; 15-04-2026; 20-04-2026; 01-06-2026; 15-07-2026 

Chrisco Tyggeruller 18 stk. - hvide

Product no. 12468 

EAN code: 5764630124684 

Use by dates: 05/01/2027; 26-02-2027; 15-03-2027; 18-03-2027; 24-03-202

Chrisco Massive politistave, 2.stk. - brune   

Product no. 12541 

EAN code: 5764630125414 

Use by dates: 26/02/2027; 15-04-2027 

Chrisco Massive politistave, 2stk. - hvide 

Product no. 12542 

EAN code: 5764630125421 

Use by dates: 05/01/2027; 20-04-2027; 01-06-2027 

Chrisco Tyggerulle m. kylling & kyllingelever, 1stk  

Product no. 12624 

EAN code: 5764630126244 

Use by dates: 01/12/2025; 05-01-2026; 15-03-2026; 18-08-2026

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What should you do if your dog has eaten a chew?

The FSA advise dog owners who have fed the affected chews to their pets to stop doing so immediately. If your dog is unwell and has been fed any of the dog chews listed, you should seek veterinary advice as soon as possible and provide detailed information to your vet about the treats your dog has been fed.

Vets have also been asked to be alert to symptoms in dogs and whether they may be associated with eating the chews, which have a long shelf life and could have been bought several months ago. 

Symptoms can include: 

• sudden behavioural changes such as howling, crying, aggression

• epileptic-type seizures  

The FSA advise that any vets who suspect cases associated with dog chews, to report them through the Animal and Plant Health Agency’s (APHA) Small Animal Surveillance.

What is ‘werewolf syndrome’?

‘Werewolf syndrome’ causes symptoms in dogs such as panic attacks, aggression, spasms, epileptic fits and in some cases death.  

You can find out more information about the dog chews and risks involved at the Food Standards Agency.