The fulfilment of pig needs and protection from diseases, through management and nutrition, are key factors in reaching maximum genetic potential, decrease costs and be prerequisite to farming success especially during tough market conditions. The keyword in pig health is “prevention” through hygiene and vaccination, which are minor investments compared to the high costs of specific diseases. Body defences are complex systems that must be instructed through vaccinations; as well as protection from poisoning and weakening, which are supported with correct nutrition favouring the establishment of a healthy gut. Seventy percent of circulating antibodies originate from the gut. A number of pathogens are able to decrease immunity through indirect and direct action. Some antibiotics and most mycotoxins decrease immunity and cause sub-clinical consequences which always result in performance losses. A well known consequence of immune depression by mycotoxins is the reactivation of chronic processes, which has been documented in Erysipelotrix r, derived infections (erysipelas, erysipele, rotlauf, mal rosso), salmonellosis, colibacillosis, swine dysentery and campylobacteriosis by the down regulation of vaccine response, as proven in erysipelas. On another side, a healthy gut decreases useless immune stimulation, thereby avoiding the waste of energy and proteins, and keeps the animal more ready to answer to real specific disease challenges.