Dog chew warning issued by FSA as pets ‘develop werewolf syndrome’

Dog owners have been urged to exercise caution after the Food Standards Agency (FSA) raised concerns regarding several dog chews from popular brands Barkoo and Chrisco.

The FSA is a department of the government dedicated to consumer safety and transparent food standards. It oversees food safety and hygiene across England, Wales, and Northern Ireland.

The department also issues recalls for products that might pose health risks or other issues to consumers. A recent precautionary warning concerns a series of particular dog chews, which could lead to “serious behavioural changes” and illness resulting from to a condition informally referred to as ‘werewolf syndrome’.

The original alarm over the products was raised back in January but has been recently reiterated. According to the FSA, if your canine companion has consumed any of these treats, you should discontinue use “immediately”. Should your dog exhibit any unusual symptoms or become ill after eating the chews, it’s crucial to consult with a vet right away. Be prepared to detail exactly what your dog has eaten, including all foods and treats.

Symptoms dogs may experience

The products in question were imported from China and distributed across various European markets. EU reports indicate a possible connection between these chews and cases of dogs displaying a rare neurological condition known as ‘werewolf syndrome’.

Symptoms associated with this condition can range from “panic attacks, aggression, spasms, epileptic fits and in some cases death”. Excessive howling has also been reported. Pet owners are urged to take this warning seriously to protect the well-being of their beloved dogs.

The FSA has assured the public there’s been “no confirmed distribution of the chews to the UK and no cases have been detected in the UK” despite rising concerns among dog owners who may purchase from online retailers.

The alarm over these chews is reverberating across social media platforms, with users advising pet owners to “stay informed” and “monitor for symptoms” to ensure their dogs’ safety.

Tina Potter, head of incidents at the FSA, commented: “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.”

Which Barkoo and Chrisco dog products are affected?

The FSA listed the affected Barkoo and Chrisco dog products, which include various sizes and packaging options of Barkoo chewing bones and Chrisco Tyggeruller with chicken, as follows:

• Barkoo kaustange natur 29 cm

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

• Barkoo kauknochen, geknotet natur 11cm

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

• Barkoo Kauknochen geknotet 24cm

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

• Barkoo Kauknochen geknotet mit Spirulina 12cm

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

• Chrisco Tyggeruller med kylling, 10 stk

Use by dates: all dates

• Chrisco Tyggeruller med kylling and kyllingelever, 100g

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

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

• Chrisco Massive politistave, 2.stk. – brune

Use by dates: 26/02/2027; 15-04-2027

• Chrisco Massive politistave, 2stk. – hvide

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

• Chrisco Tyggerulle m. kylling and kyllingelever, 1stk

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

Both companies have been approached for a statement.