This recent forum post highlights the importance of following labels when using chemicals and medications.
From the VetMed Forum - kckroq asks: "We accidentally put the dog flea repellent (like Advantage) on our cat. We bathed him about 4 hours after application and when we realized the terrible mistake we made. He seemed better, so we went to bed for the night. When we woke up, the cat looked like he was in shock, shaking, eyes glossed over. He is at the vet now getting fluids but they are not sure what to expect. Has anyone else experienced this?"
Update FAQ: Help - I Just Put Dog Flea Control on my Cat