We bought this product after finding a flea on our female boxer. We gave the treatment to two of our three boxers and they became sick and threw up during the night. When we got up the next morning, the female was still sick to her stomache, and our two year old male was so sick that he could hardly walk. It seemed like he was having trouble with his balence. We called our vet and she recommended that we call Sergeants and tell them the situation so we did. This was the biggest waste of time that I have ever seen! They acted like we didn't know what we were talking about, wouldn't tell us much and insisted that our vet call them. I called my vet again and she told us to take Dawn dish soap and wash both dogs two times each. the only thing she could do is give a i.v. if he dehydrates. (Thank god we were able to get him to drink some water all day. After his second bath he started to act like himself again. THEY NEED TO PUT ANY AND ALL SIDE EFFECTS ON THE BOX !! THEN THE CONSUMER CAN MAKE A INFORMED DECISION ON USING IT OR NOT. as for me I will Never use any other products by Sergeants again. they don't understand it's not just a dog, it's a member of the family, like ones own child.