I gave this to my Aussie Bulldog for the first time last night and she has been vomiting ever since. She keeps arching her back like she has a sore tummy and is lethargic. So annoyed as this cost $140 for 6 months worth and we won't be using it again.

I have been using this product on my Maltese Poodle for a few years now and never had an issue. She has never had a negative reaction to the product and gobbles it up each month just like a treat! Gives me peace of mind that she is protected from nasties.

Our small dog has had no issues since using this product. We have to wrap the pill in ice-cream for him to eat it though and this is OK as its once a month. The RRP on this is outrageous and with an automated on-line search I can still get it for around $13 per pill buying packs of 6 or 9. The dog does still get the occasional Tick and we have to inspect him every day basically for Ticks. No issues with Spectrum other than the cost.

Our bigger dog 50 lbs is very lethargic and not acting her normal self. Our little dog 10lbs has had bad diarrhea and extremely lethargic. Neither dog is acting normal.

Maybe it works on worms but didn't seem to have any effect on fleas. It says on the packet it will not kill fleas but prevents re infection. Both my dogs had fleas during treatments. "did the dogs pick the fleas up from outside"? well the fleas today were tiny so seemed to be new borns. I am going to change products but in all fairness we have people visiting us everyday with their two dogs and have cats so maybe impossible to control xx

I have used Sentinel Spectrum for many years and have seen zero side affects.
The product works well and we not had fleas or worms.
I highly recommend it from puppy through to an aged dog.

I gave this to my dog on December 31st because I was off of work and like to monitor a reaction, of any. From this day on, and it is now Jan 8, my dog has rarely had anything to eat. One side affect of this drug is anorexia. I have never experienced this issue with my dog and would appreciate further studies to determine if this drug is safe as I really dislike the idea of having further vetenary bills on top of what this medication costs. So, the manufacturer needs to put out a warning to dog owners and veterinarians that this is a big problem.

We’ve had our mixed breed on Sentinel his whole life (8 yrs), and we are suddenly having a flea problem. He doesn’t have a history of fleas. I don’t know if the formula changed, or what happened, but lately it seems that the Sentinel isn’t even stopping the cycle. If I have to buy a separate pill for fleas, then what is the point to keep buying this?

I gave this product to all my pugs and one had a terrible reaction. The next day he acted lethergic and would not eat. Within 24 hours he was having trouble walking with issues in his rear. After 300.00 at my vets and 3 different meds it took him a whole month to come back. It hit his nervous system hard. I will not take the chance of it hurting my other dogs so will not give to any of my animals again.

Feed it to your dog with a full meal just like a treat. My dog would not know what a flea was, and has never had intestinal worms. Easy, quick, fuss and mess-free this is the simplest method to keep your dog Heartworm-free and never know a flea. It is a once-a-month chew, and the dog loves it. The product is highly efficient, and you will never have smelly or sticky fur on the back of their neck again. My Belgian Shepherds have never experienced nasty side-effects and each month they all think that it is "treat time". I have used this product since its introduction to the Market and have never had a problem.

My healthy happy 7.5 year old english bulldog started having seizures 8 hours after first dose. 2 months later she is on seizure meds and still suffering. Terrible chemical.

Have used this product for the last 6 months on my puppy, it’s amazing, use every month and he’s never had any problems regarding fleas or ticks. 100% would buy again.

Used on two dogs since pups. One lived until age 15. The 12 year old Havanese is still with us. The loved their monthly treat. Never a flea in 15 years. No health problems whatsoever. We used Sentinel Flavored Tabs.

I really hate to be negative, but this medicine made my 10 lb morkie not want to eat her food. She was lethargic and has thrown up several times soon after having the medicine. After the first dose she seemed a little lethargic. The last couple of months her reaction has gotten worse after each dose. After reading the reviews I can see it is not just my imagination or just my sweet Lola. I am going to have to throw the rest of my medicine away.

I have been using this on my 2.5 year old Pomeranian since he was 3 months old and he’s never had fleas, heartworm or worms. He loves the chew and thinks it’s a tasty treat. No side-effects. Thumbs up!