According to the msds (material safety data sheet) for Rid-X, which can be found here: http://188.8.131.52/search?q=cache:NM4MONxAH20J:www.reckittprofessional.com/customer_services/msds/dist/370893_r.pdf+%22rid-x%22%2Bmsds&hl=en&ct=clnk&cd=1&gl=us
If accidental ingestion occurs, you should rinse out the mouth with water, and contact a physician (or in this case, a veterinarian) or poison control if symptoms develop. However, after reading a little further down the page, it says that there are no expected symptoms because Rid-X is non-toxic
Just to be on the safe side, I would suggest you rinse the dog's mouth out and then watch for things like vomiting, diarrhea or behavioral changes (stumbling, disorientation, lethargy and unwillingness to eat). If you see anything that is out of character for your dog, I would seek medical attention at an emergency clinic.
I hope this helps.