I have seen terrible advice given out by well meaning people but people who simply do not know the facts. For example I have seen a person ask if they can give aspirin to a cat and they were told “Sure, I gave it to my dog so I do not see why you cannot give it to your cat”. Of course the truth is that aspirin is somewhat risky for dogs (although if carefully dosed it is fine) but very dangerous to cats and even a small amount can be fatal.
What is really great about the question section for vets on PetMD is that it is not just limited to questions about cats and dogs either. PetMD allows you to ask questions about birds, horses, reptiles, or other exotic pets.
If you have a pet emergency it is best to contact your veterinarian. Most vets do have 24 hour services and are available even when their office is closed. For non-emergency situations or times when you just have a simple question, try asking a veterinarian on PetMD.com