Professional care is most often led by a veterinary physician (also known as a veterinarian, veterinary surgeon, or 'vet'), but also by paraveterinary workers, such as veterinary nurses or technicians. This can be augmented by other paraprofessionals with specific specialties, such as animal physiotherapy or dentistry, and species-relevant roles such as farriers. Veterinary science helps human health through the monitoring and control of zoonotic disease (infectious disease transmitted from nonhuman animals to humans), food safety, and through human applications via medical research. They also help to maintain food supply through livestock health monitoring and treatment, and mental health by keeping pets healthy and long-living. Veterinary scientists often collaborate with epidemiologists and other health or natural scientists, depending on type of work.

Ethically, veterinarians are usually obliged to look after animal welfare. Veterinarians diagnose, treat, and help keep animals safe and healthy. The first attempts to organize and regulate the practice of treating animals tended to focus on horses because of their economic significance. In the Middle Ages, farriers combined their work in horseshoeing with the more general task of 'horse doctoring'. The Arabic tradition of Bayṭara, or Shiyāt al-Khayl, originates with the treatise of Ibn Akhī Hizām (fl. late 9th century). In 1356, the Lord Mayor of London, concerned at the poor standard of care given to horses in the city, requested that all farriers operating within a 7-mile (11-km) radius of the City of London form a 'fellowship' to regulate and improve their practices. This ultimately led to the establishment of the Worshipful Company of Farriers in 1674. eanwhile, Carlo Ruini's book Anatomia del Cavallo, (Anatomy of the Horse) was published in 1598. It was the first comprehensive treatise on the anatomy of a nonhuman species. Veterinary care and management are usually led by a veterinary physician (usually called a veterinarian, veterinary surgeon or 'vet' - doctor of veterinary medicine or veterinary medical doctor). This role is the equivalent of a physician or surgeon (medical doctor) in human medicine, and involves postgraduate study and qualification.

In many countries, the local nomenclature for a vet is a protected term, meaning that people without the prerequisite qualifications and/or registration are not able to use the title, and in many cases, the activities that may be undertaken by a vet (such as animal treatment or surgery) are restricted only to those people who are registered as vet. For instance, in the United Kingdom, as in other jurisdictions, animal treatment may be performed only by registered vets (with a few designated exceptions, such as paraveterinary workers), and any persons calling themselves a vet without being registered or performing any treatment is illegal. Most vets work in clinical settings, treating animals directly. They may be involved in a general practice, treating animals of all types; may be specialized in a specific group of animals such as companion animals, livestock, laboratory animals, zoo animals, or horses; or may specialize in a narrow medical discipline such as veterinary surgery, dermatology, cardiology, neurology, laboratory animal medicine, internal medicine, and more.

As with healthcare professionals, vets face ethical decisions about the care of their patients. Current debates within the profession include the ethics of purely cosmetic procedures on animals, such as declawing of cats, docking of tails, cropping of ears, and debarking on dogs. A wide range of surgeries and operations is performed on various types of animals, but not all of them are carried out by vets. In a case in Iran, for instance, an eye surgeon managed to perform a successful cataract surgery on a rooster for the first time in the world. Veterinary research includes prevention, control, diagnosis, and treatment of diseases of animals, and basic biology, welfare, and care of animals. Veterinary research transcends species boundaries and includes the study of spontaneously occurring and experimentally induced models of both human and animal diseases and research at human-animal interfaces, such as food safety, wildlife and ecosystem health, zoonotic diseases, and public policy.