Ideally, animal models of bronchial asthma should exhibit most if not all features of human bronchial asthma. The general aim of developing such animal models has undoubtedly been to reproduce the human disease in order to study its pathophysiology and pathogenesis. A careful review of the literature indicates that allergic bronchoconstriction in the guinea pig, dog, sheep, and monkey exhibit only some of the typical characteristics of bronchial asthma in man. In keeping with human asthma, allergic animals exhibit nonspecific airway hyperresponsiveness and physiologic responses to antigen challenge resembling those in man. Also, the immunologic pathways leading to bronchoconstriction and mucociliary dysfunction are essentially the same in allergic animals and patients with allergic bronchial asthma. On the other hand, spontaneous and persistent bronchial obstruction, typical features of human bronchial asthma, have not been observed in animal models. Likewise, the pathologic lesions of human bronchial asthma have not or only incompletely been reproduced in allergic animals. At the present state of our knowledge, one might therefore conclude that allergic bronchoconstriction in animals is an excellent model of antigen induced bronchoconstriction in man as it is observed in the laboratory, but a less satisfactory model of spontaneous bronchial asthma. The animal models represent useful research tools to study some pathophysiologic aspects of bronchial asthma as long as the limitations of the model are recognized. Which of the four currently used species is chosen for a given experiment and whether new models need to be developed depends upon the physiologic question to be answered.