I bought the Seresto collar after reading some great reviews on it. I also read the one star reviews and a lot of them said it just didn't work. I decided to take that chance. However, if I had kept reading, I would have seen the other 1 star reviews that claimed this product had a negative effect on their dogs and I wouldn't have bought it. Well, I had a similar experience. This product is incredibly dangerous. I put this on my 9 year old dog and less than 24 hours later, he was lethargic, shaking, and seem to have pain on his hind legs. I took off the collar immediately after that and a few hours later (after reading someone's review saying that their dog died because they didn't rinse him off after removing the collar) I gave him a bath, but he was still lethargic and wouldn't get up to eat or drink. Today he seems slightly better and more energetic, but he still won't jump up on the bed. I'm hoping that he continues to improve. I'll probably be taking him to the vet tomorrow if I see that he's still not 100%. Please don't take a chance with your animals. Just don't use this product. It's truly not worth it!

While these kept fleas at bay... I highly recommend staying away from this product. My 12 lb chihuahua started having seizures within 1 week after putting collar on, I had no idea it was the collar and we ended up leaving it on for 8 months and then bought another the next year. He continued to have seizures and it earned on me that it all started after the collar was started, at that point, my other chihuahua started having seizures....i will be asking Bayer for my money back, this is very scarey and shouldn't happen to any animal. I have spent over $300in these collars and for what? Health scares??

Take a look at the photo. She has been wearing the collar for 9 days, way more than enough time for the collar to be 100% effective. Then how does a tick implant itself just 2 inches from the colar, and live?

If the tick was on her tail, I could be more forgiving, but this is a joke. Still scratching from fleas too.

I didn't buy the collar from the cheaper resellers, to avoid getting scammed by a fake product. This was sold and fulfilled BY AMAZON.

There is no excuse for this. The collar is innefective.

We have an outdoor dog that is absolutely covered in fleas nearly year round, since we don't get hard freezes here in North Carolina. We've tried Frontline, Capstar, Program, Advantage, flea collars, flea shampoos, spraying fipronil in the area around the barn where he lives, diatomaceous earth, brewers yeast and garlic, cedar oil and cedar chip bedding, and nothing worked. We even used corn oil to coat and suffocate the fleas, which worked but only for a day or two. I was convinced that these are zombie fleas and immortal. And the poor dog was miserable and scratching.

I hesitated to pay $50 for a flea collar that might not work, but took the chance and ordered this Seresto collar. We put it on the dog two days ago, and I'm amazed! The first day, we noticed that the fleas on the front half of his body were gone. Today we didn't find one single live flea on him, nostrils to tail tip. We did notice some dead ones on him. This is the first thing we've ever found that got rid of/killed the fleas! He was lying happily in the sun this morning, not scratching or twitching, for the first time in months.

Since the collar worked, I've also ordered one for our little indoor dog and the indoor cat, who also have fleas (but not as many). If these collars really kill the fleas for 6-8 months, they are worth every penny of the cost. I will update my review after a few months, to report whether or not the flea killing effect lasted. I'll also keep an eye out for irritation, baldness or oozing sores where the collar lies (since some pets have had an adverse reaction to collar) and report that here if it happens.

For now, I'm very, very happy to have something to help combat the fleas!
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Edited 6 June 2017: It's only been a few weeks but I wanted to update. No fleas on the pets - if they pick one up in the grass it hops off without biting. The small dog was a little lethargic for a day or so (just acted tired and didn't want to play - he was still eating) after we put on his collar, but we kept a close eye on him and he was back to himself on the third day. No rawness, sores or extreme symptoms from any of the pets. I also set off some Hot Shot flea fogger/bombs in our carpeted bedrooms, where we had fleas (the pets sleep with us). Between the collars and the bombs, we are finally, at long last, flea free! I'll update again at the end of the collars' lives to report how long they lasted. Buy this collar - you won't regret it!

I bought this product at Amazon last year at $35. and Bayer has raised the price to $53...$18.00 more
for the same thing in a matter of months. GREED, GOUGING, SELFISH, UNFAIR, I can't think of
anything worse to call UNSCRUPULOUS PEOPLE that take advantage of people just because THEY CAN.
When I find something that works well and has a price that God approves of I will let you all know. The
Bayer Co. has 100 years of unscrupulous business practices and I hate buying anything from them or
doing any business at all with them. One thing, Cedar, essential oil helps temporarily. Fleas hate the scent,
and the dog stops scratching until I let her out again. If anyone out there has found anything that works
long term ONLY, please post it.