Because my dog interacts with other dogs a lot, when he developed a "cough" I immediately took him to the vet. He had no fever, is eating and drinking normally and his activity level is normal - he doesn't at all act like a sick dog. I have kept him away from other dogs to avoid getting them sick. The vet diagnosed him with kennel cough and put him on Doxycycline 100 mg - he takes 1 1/2 pills twice a day. He started them on Tuesday.He has also had a Bordetella vaccine. His cough seems to be getting worse instead of better. We cut our walk quite short this morning because he was really coughing and coughing up a lot of phlegm (gray and pale yellow). I'm concerned that he may be getting worse though he still doesn't act sick.