Urgent warning over dog toy that can cause ‘werewolf syndrome’
Dog owners have been warned against feeding their pets a certain brand of chew bones that can cause sudden behavioural changes known as ‘werewolf syndrome’.
The Food Standards Agency (FSA) said the China-made chews can elicit alarming symptoms including panic attacks, aggression, spasms, epileptic fits and in some cases death.
It comes after a health authority in the Netherlands cautioned owners over feeding their dogs cheese sticks and chew bones from the company Barkoo following the reported death of a dog there.
There is no confirmed distribution of the products to the UK and there have not been any cases detected here, the FSA said.
But Tina Potter, head of standards at the 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.’
The FSA said it is liaising with European countries to develop a better understanding of the issue.
Check which products are affected
Barkoo kaustange natur 29 cm
Packaging: bags of 570 grams (with 3 chewing bones)
Code on packaging (see photo): 1148655 MHD 04.2027 3200PF027
Barcode: 4260077047292
Barkoo kauknochen, geknotet natur 11cm
Packaging: bags of 150 grams (with 3 chewing bones)
Code on packaging (see photo): 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 (see photo): 1148657 MHD05.2027 3200PF027
Barkoo Kauknochen geknotet mit Spirulina 12cm
Packaging: bags of 180 grams (with 3 chewing bones)
Barcode: 4260077047261
Code on packaging (see photo): 1148654 MHD 06.2027 3200PF027
Chrisco Products:
Chrisco Tyggeruller med kylling, 10 stk (No image available)
Item number: 12457
EAN code: 5764630124578
Use by dates: all dates
Chrisco Tyggeruller med kylling & kyllingelever, 100g (No image available)
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 (No image available)
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 (No image available)
Product no. 12541
EAN code: 5764630125414
Use by dates: 26/02/2027; 15-04-2027
Chrisco Massive politistave, 2stk. – hvide (No image available)
Product no. 12542
EAN code: 5764630125421
Use by dates: 05/01/2027; 20-04-2027; 01-06-2027
Chrisco Tyggerulle m. kylling & kyllingelever, 1stk (No image available)
Product no. 12624
EAN code: 5764630126244
Use by dates: 01/12/2025; 05-01-2026; 15-03-2026; 18-08-2026
Dog owners who have already given the affected chews to their pets are advised to ‘stop doing so immediately’.
If your pet has fallen ill after using or ingesting the chew, you should seek veterinary advice and give your vet as much information as possible about the foods the dog has been fed.
The FSA also provides advice for vets, saying they should be alert to symptoms in dogs presenting at their surgeries and whether they may be associated with the consumption of the chews, which have a long shelf life and may have been bought several months ago.
They include sudden behavioural changes such as howling, crying, aggression and epileptic-type seizures
If vets suspect cases associated with dog chews, they can report them through the Animal and Plant Health Agency’s (APHA) Small Animal Surveillance.
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