The basic principles of homeopathy, and its legal and scientific foundations, are discussed in an overview to address the positions of the World Health Organization (WHO) and the commission of the European Union (EU) on complementary medicine. According to the WHO, the antimicrobial resistance problem poses a global threat. The EU Commission’s current One Health Action Plan requests research in complementary medicine, the WHO urges member states to include complementary medicine in their national health policies. Regarding external evidence on the general use of human and veterinary homeopathy, evidence level 1a studies are reviewed. Focusing on the external evidence on the use of homeopathy in infections, some evidence level 1a, 1b, 2c studies, and a case report, are described in more detail. In conclusion, evidence for the effectiveness of human and veterinary homeopathy in general, and in particular, of homeopathic treatment for infections, is available. Especially, individualized homeopathy demonstrates effects at all quality levels according to Cochrane criteria, even in the methodologically high-quality studies. As in most areas of veterinary medicine and medicine, further good/excellent studies are necessary. In compliance with the principles of homeopathy, further methodologically high-quality trials focusing on the homeopathic treatment of infections are the next logical step. The selection of the simile (individually fitting homeopathic medicinal product) by appropriately trained homeopathic doctors/veterinarians is essential for the effectiveness of homeopathy. Implementation of studies at university facilities is a prerequisite for quality assurance. Consequently, further integration of homeopathy at universities is a necessary requirement for the patients’ best interests.