Smellables are anything that are considered attractive in smell to wildlife while in the backcountry. Smellables are required to be put into the bear bags each night before going to bed and are taken down in the morning.
Important examples of smellables are: food, medication, contact lens solution, anything cosmetic like toothpaste and anything with a chemical scent that might attract a bear into your campsite. This includes gas tanks for stoves and items used to clean food should also be considered smellables. Even a water bottle that has been carrying Kool-Aid should be considered a smellable.
Deodorant is usually not allowed in the backcountry.