Rats have an excellent sense of smell. There are some of the strong flavors cause them fear. These include odors of certain plants and the smell of the enemy - so many sprays, repellents contain rodent’enemy urine, such as coyotes. The list of unpleasant rats plants includes peppermint, rosemary, chamomile, black pepper, garlic, tarragon and some other herbs. They can be used in the natural form and in the form of essential oils. Learn more about natural rat repellents, read the review 5 Best Ways of Getting Rid of Rats.