This post doesn't apply to everyone – but it might apply to you. Today, I want to shed light on a topic that is very close to my heart: dog chews. More specifically: dangerous chews that may be linked to a disturbing phenomenon – the so-called Werewolf Syndrome.

Maybe you've heard of it. Maybe not. I hope this post reaches as many dog owners as possible – especially those who, like me, suddenly had a completely changed dog and are desperately searching for answers.

If your dog is suddenly not himself...

It started very suddenly for us. One of my dogs – a loving, social male, with me since he was a puppy, from a reputable breeder – changed overnight. From one moment to the next, he was restless, anxious, irritable. He had panic attacks, cried for hours without reason, couldn't sleep. He suddenly attacked our other female dog, with whom he had previously been inseparable. It was as if someone had flipped a switch.

I couldn't believe it. I had worked so much with him, socialized him, trained him, loved him. And suddenly he was unpredictable. We hardly got any sleep, the second female dog became anxious again – and I myself was completely exhausted, both mentally and physically. It was a nightmare.

For a long time, I wondered what I must have done wrong. But then, after more than half a year of vet visits, behavioral therapy, and countless research, I stumbled upon a term: Werewolf Syndrome in dogs.

 

What is Werewolf Syndrome in dogs?

The term was coined by the media, but it has nothing to do with the human medical condition. It refers to a neurological disorder in dogs that manifests itself through sudden, extreme behavioral changes. According to reports, dogs across Europe are affected – and there is a concrete suspicion: poisoning by processed chews, especially those made from bleached rawhide.

Typical symptoms:

- extreme anxiety

- sudden whining or barking

- aggressive behavior without trigger

- trembling, heavy panting

- uncoordinated gait

- disorientation

- uncontrolled movements

- epileptic seizures

- panic attacks

- noticeable eye contact or staring

- sudden restlessness, day and night

Symptoms often appear suddenly – in previously completely inconspicuous, well-behaved family dogs.

 

Latest findings (as of 2025):

A current study (March 2025) on ResearchGate and investigations by TiHo Hannover and authorities in Denmark, Finland, and the Netherlands indicate a possible connection between certain chews and these neurological symptoms. The affected products were examined for neurotoxins – a complex and lengthy process, as many substances could be involved.

Several recalls concerned chews (e.g., the Barkoo brand) that were also available in Germany. Affected batches can be found on the website of the Dutch authority NVWA.

A manufacturer under observation: Jiangsu Huanhuan Pet Foods

In my research, I came across the manufacturer Jiangsu Huanhuan Pet Foods – one of the largest producers of rawhide chews in China. Products from there look exactly like those now being warned about: heavily processed, bleached, pressed into knots or rolls. Whether affected batches actually come from there is not confirmed – but there is reason for caution.

Here's an example: www.cnlovefun.com (This page shows many products from this manufacturer – purely for illustration.)

 

What can you do if your dog is affected?

- Immediately stop all suspicious chews

- Keep packaging with batch numbers

- Go to the vet as soon as possible – ideally focusing on neurology or behavior

• Document everything: behavior, symptoms, videos
• Report the suspicion to TiHo Hannover or to national food authorities
• Exchange information with other affected individuals

 

Important: According to current findings, the prognosis is positive in most cases if the trigger is identified and consistently removed. My dog's condition has noticeably improved – even though the journey was tough.

 

What I want to impress upon you

Avoid heavily processed chews, especially bleached rawhide. Pay attention to the origin. I now completely avoid products from China or those with unclear labeling. Instead, opt for natural chews – or make them yourself! For example, you can cut chicken breast into strips and dry them in the oven or a dehydrator. That way, you know exactly what you're giving your dog.

If you need tips – feel free to write to me. I'll help where I can.

 

Exchange with other affected individuals

If you are affected yourself or are looking for more testimonials, you can also join the following Facebook group:

Werewolf Syndrome in dogs – Sharing experiences: https://www.facebook.com/groups/1311299406712266/?ref=share

Note: This is a private group for dog owners to share experiences. The content does not replace veterinary advice.

 

Conclusion: Better safe than sorry

I sincerely hope that my post reaches some dog owners – especially those who have been wondering for weeks what is suddenly wrong with their beloved dog. You are not alone. And there is hope.

Take care of your dog – and trust your gut feeling.

If something seems "off," it might just be. Better to question it too much than act too late.

I wish all those affected much strength and courage.

And my deepest condolences to all those who have already lost their dog. You are not forgotten.