Abstract: An agent for improving mobility and general health of senior companion animals is provided whereby said agent contains one or more substances selected from the group consisting of a GABAA receptor agonist, a GABAB receptor agonist and a GABAA receptor enhancing substance as an active ingredient. Compositions containing said agent, including a pet food additive and a pet food, as well as methods of administering said compositions to senior companion animals are also provided.

Abstract: A preparation or a pet food comprising an edible carboxylic acid, edible hydroxycarboxylic acid such as fumaric acid or a salt thereof is administered or fed to a pet. The content of the edible organic acid or a salt thereof is, in terms of the edible organic acid, about 0.1 to 99.9% by weight for the preparation such as a solid preparation and about 0.01 to 10% by weight for the pet food such as a dry food. The dose of the edible organic acid or a salt thereof is, in terms of the edible organic acid, about 5 to 500 mg/day/kg of body weight. The preparation and pet food have an improved palatability and safety in comparison with a conventional urine-acidifying agent, thus the administration or feeding of said preparation or pet food prevent or treat urinary calculosis in a pet even in a small amount.