Are Any Herbs Bad For Dogs?

Are Any Herbs Bad For Dogs? As far as we know, most herbs—your rosemary, thyme, basil and dill—are safe for cats and dogs, but there is one that frequently colors a person’s garden that can cause a sometimes severe—and definitely strange— illness. What cooking herbs are toxic to dogs? Mace. Cocoa. Marjoram. Cannabis. Tarragon. Borage.