Both Glandex and Metamucil are examples of dietary fiber supplements that can be given to dogs in order to promote the healthy function of the anal gland. While Metamucil is a supplement made from psyllium husk fiber that may be used to support overall digestive health, Glandex is a proprietary composition created especially for dogs and cats that experience recurrent anal gland issues. Before giving your pet any vitamins, it is always advised to speak with a veterinarian.