I gave my 2 year old little cat the Hartz flea and tick drops (Phenothrin) in the morning. At the same time I gave my 10 year old cat the last dose of Revolution (Selamectin) flea and tick drops. I left the house for the day and when I returned that evening my 2 year old cat was experiencing hypersalivation and rapid breathing. She seemed uncomfortable and agitated. I thought she would overcome it so I let her be for a few hours and then started to worry when it continued. Meanwhile the 10 year old was fine. When I went on line I immmediately found a court case where a woman was sueing Hartz for damages and this site. I immediately washed my 2 year old in the sink in an effort to get all the medication off. She stopped the hypersalivation but is lethargic this morning and still is breathing fast. I will return the product to the store along with a copy of this web site to show that they should discontinue sales. I think she will be allright – should she see a vet?