Dog owners are being warned to avoid a chew toy from China that can cause sudden behavioural changes that people have started calling “werewolf syndrome”.
The Food Standards Agency (FSA) issued a warning on Tuesday, saying the China-made chews can elicit alarming symptoms including panic attacks, aggression, spasms, howling, epileptic fits and in some cases death.
It follows the EU expressing concern about the chews and a possible link to serious behavioural changes, as other countries have reportedly had cases of dogs affected, including the Netherlands.
According to the FSA, there is no confirmed distribution of affected products to the UK.
Despite this, head of incidents at FSA, Tina Potter said: “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.”
Affected products include:
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
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
The FSA said it is liaising with authorities in affected EU countries to gain more understanding of the issue.
Dog owners who have already given the affected chews to their pets are urged to “stop doing so immediately”.
They have been further advised that if their dog is unwell and has been fed any of the items listed, they should seek veterinary advice and provide detailed information to the vet about the foods and treats they have fed their pet.
If vets suspect cases associated with dog chews, they can report them through the Animal and Plant Health Agency’s small animal surveillance group.
