People, I have to warn you: do not and I repeat do not, under any circumstances, use CostCo’s “Kirkland Signature” brand of flea & tick control! We’ve just had a disastrous experience not even 24 hours after applying the product to our cats.
I’ve used Advantage, Frontline and Revolution on our six cats for years. I didn’t know that CostCo even had its own brand of flea & tick treatment until Mr. Beale and I attended a crafts fair and CostCo had a table set up where they were advertising this stuff and selling memberships. Well, we’ve been CostCo members for years so we thought, “cool, a cheaper flea & tick treatment, what’s not to love?”
Hair loss! And a nasty mess all over the house, that’s what! OMG, this is the worst stuff ever. Almost as soon as we applied the treatment our cats’ hair started falling out. And the stuff doesn’t absorb like other flea products, so it leaves huge greasy stains everywhere — furniture, bedding, you name it. I had to wash the sheets on our bed after Quinn took his afternoon nap on it!
Look:

Quinn’s hair started falling out ….

So did Como’s ….. finding this stuff EVERYWHERE ….
…. and I won’t bore you with photos of my dirty laundry. I’m wishing I’d read the product reviews at Amazon before using this stuff because the reviews are universally negative. I’m so disappointed in CostCo, it appears this product has been poisoning peoples’ pets for over a year, and there they are promoting it at a crafts’ fair? Shame on them.
I’m worried sick that more serious symptoms will appear. Our cats are like our children, and the idea that I’ve actually poisoned my animals has me frantic. I’m going to call the vet as soon as they open and see what they recommend, I might be spending my day giving six cats a bath. :-0
Anyway, it’s too late for me, but save yourselves! Do not use this product!

Quinn in happier times, like, last week.
[UPDATE]:
Just spent about 2 hours on the phone with the vet, CostCo, product manufacturer, Animal Product Services Safety Center, etc. Diagnosis: bathing in Dawn dishwashing liquid.
They are not amused:

Pissed off kitty.

Misery loves company.