I usually use Frontline to control fleas and ticks on my 3 cats, but one month my budget was tight, and I thought I’d just use an OTC drop. I selected Hartz, as it’s a name I recognized and trusted. The girls objected strenuously immediately upon applying the drops, and during the next couple of days I noticed a lot of attempted grooming of the application site and irritable behavior in general. On the third day, all the hair fell off between their shoulder blades, and the flesh was covered in oozing scabs. They were miserable. They healed within a couple of weeks except for one, who I finally had to take to the vet to rectify. Her skin and hair remained scabby and missing for almost 2 months. I had to keep her on antibiotics the entire time. What really disturbed me was the knowing look exchanged by the workers in the vet’s office before they told me they see this all the time with Hartz drops. I’ve been warning everyone I know about Hartz. I can’t believe they have this on the market.