The short answer: No.
The long answer: Pickles are cucumbers or other vegetables that have been soaked in a saline solution for an extended period of time. The liquid used for fermentation is often mixed with salt, vinegar, and seasoning, making it dangerous for dogs due to high sodium content and the possible spices used.
If your dog eats large amounts of pickles, salt can cause poisoning which can manifest through excessive thirst or urination, vomiting, diarrhea, decreased appetite, lethargy, lack of coordination, tremors, seizures, or coma. Salt is especially harmful for dogs with compromised livers. Additionally, spices such as onions, chives, and garlic are often included to add flavour to the saline solution. These vegetables are known to be lethal to dogs, and can cause red blood cell destruction that can lead to anemia. Lethargy, pale mucous membrane, elevated respiratory or heart rate, vomiting, and decrease in appetite are some of the signs of onion or garlic poisoning.
What to do if your dog accidentally eats pickles: Don’t panic. It’s totally fine for your dog to eat a slice or two of pickles. However, if you notice that he has consumed a considerable number of pickles, call your veterinarian immediately for life-saving advice. You may be asked to induce vomiting and give activated charcoal to your dog, or be required to bring your dog to the emergency clinic.
In summary: Though pickles are not intrinsically toxic to dogs in small doses, your pooch won’t benefit from eating them. The process of pickling removes the nutritional value of vegetables, so you’re better off feeding him fresh and crunchy cucumbers packed with potassium, fiber, and vitamin C.