My 6 year-old Shihtzu-mix reacts to thunder, fireworks and other similar or unusual noises. On one recent occasion, I gave her the recommended dose of Well & Good Calming Aid sold by Petco to calm her. Since she had gotten our other dog agitated, I also gave him some of the calming aid. Based on their weight, the dose is 1/2 of a soft chew, which is very difficult to break evently in half because it crumbles. Our Shihttzu ate her dose and also scarfed up her buddy's dose when he dropped it. Within a few hours, she was so lethargic, she wouldn't eat and just let her face fall into her food bowl. For a normally voracious eater, this was shocking. We took her to the vet and brought along the package of calming aids. The vet noted that it contained Hops which , unbeknownt to me, is very toxic for dogs. The vet gave her subcutaneous fluids to help her flush the calming aid out of her system faster. The next day, she developed a hemorrhage in her eye. On the following day, the other eye hemorrhaged. And, although the lethargy improved, she was still not her normal boisterous self. Two more visits to the vet and after several tests and $800 in vet bills, they found she had extremely high blood pressure. She got meds for a week to lower her pressure and a follow-up appointment after going off the meds for a day showed that her pressure was back to normal. All of the medical issues were attributed to the calming aid and not to any intrinsic health problem. Our Shihtzu is a rescue and is not a tiny pedigree; she weighs 17 lbs. The dose of the calming aid is 1/2 chew up to 26 lbs. I hate to think what might happen to a tiny dog who gets an overdose. There are no warnings on the package and the soft chew itself makes it almost impossible to cut or break it into an accurate dose. This calming aid is dangerous. Why it contains a toxic substance like hops is a mystery and why it is sold by Petco is also a mystery. Hops is not a well-known canine toxin. Pet owners trust that Petco is not selling something that is dangerous or toxic. Don't give this product to your pet.