A furry friend offers many health benefits, so return the favor by taking good care of your dog. There’s nothing better than getting out into the great outdoors with the family and your pet for a lovely autumn hike. And if you’re anything like us, you probably think nothing of letting your dog frolic in whatever body of water he happens upon. However, some freshwater ponds contain blue-green algae, which contain toxins that can cause dogs to suffer from gastrointestinal distress like vomiting or diarrhea, liver failure or possibly death. If you approach a lake or pond and the water is green, YOU and your pet should avoid it. Though not as dangerous to humans, blue-green algae can cause skin rashes, sneezing, coughing, a runny nose and eye irritation in people.