According to WebMD, Pedialyte is safe for dogs when combined with an equal amount of water. Electrolyte solutions are commonly used when dogs have extended bouts of diarrhea.The K9 Thirst Quencher is a electrolyte solution designed specifically for dogs.
WebMD indicates that some dogs do not like the flavor of electrolyte solutions, so plain water or water mixed with low-salt bouillon sometimes encourages a dog to drink. When a dog suddenly comes down with diarrhea, it is important to withhold food for 24 hours in order to rest the digestive system; this usually stops diarrhea.
WebMD lists potentially serious symptoms that sometimes accompany diarrhea, such as bloody or black stool, vomiting, fever, muscle weakness and depression. If any of these appear or if the diarrhea lasts for more than 24 hours, a veterinarian should be consulted.