Peanut butter earns its place in the treat drawer: dogs love it, it hides pills gracefully, and it turns a lick mat or filled toy into twenty minutes of calm. The best choice is an unsalted peanut butter whose ingredient list is essentially just peanuts — no xylitol, minimal added salt and sugar.
Two moderating factors are worth keeping in mind. First, peanut butter is dense in fat and calories, so it should stay an occasional treat — veterinary guidance is that treats of all kinds should make up no more than about 10% of a dog's daily calories, and a spoonful of peanut butter uses that budget quickly, especially for small dogs. Second, the xylitol risk is not theoretical: sugar-free and "no sugar added" peanut butters that contain it are on store shelves, and even a small amount of xylitol can cause a dangerous drop in blood sugar. Read the jar once, and you can relax about it afterwards.
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This page is informational and is not veterinary advice. If your pet has eaten something risky, contact your vet or an animal poison control line right away.