Mycobacterium vaccae is a nonpathogenic species of the Mycobacteriaceae family of bacteria that lives naturally in soil. Its name originates from the Latin word, vacca (cow), since it was first cultured from cow dung in Austria. Research areas being pursued with regard to killed Mycobacterium vaccae vaccine include immunotherapy for allergic asthma, cancer, depression, leprosy, psoriasis, dermatitis, eczema and tuberculosis. M. vaccae may serve as one biological mechanism by which historical and Ayurvedic folk remedies such as Aqua omnium florum offer their benefit.