Diarrheal diseases or scours continue to be one of the most common health problems in young animals. Diarrhea is caused by several pathogens, making it one of the hardest diseases to control and prevent. The financial losses resulting from scours are considerable, including costs for treatment, negative weight gain and death. In addition, much work is invested in the special care of sick calves. There are two general principles of therapy for diarrhea: treat the cause and treat the symptoms. The causes of scours can be classified as either infectious or non-infectious. Within the environmental influence, deficiencies in the improper administration of milk and inadequate housing conditions are the most important non- infectious causes of diarrhea. Even with excellent animal management systems, enteropathogenic organisms can infect young animals because of their immature immune systems and limited energy and nutrient reserves. Viruses such as rotavirus and coronavirus, in addition to bacteria are the most important pathogens. Parasites like Cryptosporidium spp. and coccidia are also frequent causes of scours in calves. Regardless of the ethology and pathogenesis, scouring calves lose large amounts of fluids, electrolytes and buffering agents, causing severe health problems. There are two general principles of therapy for diarrhea: treat the cause and treat the symptoms. For non-infectious causes, the most important preventative action is the elimination of any negative environmental influences. In the case of infectious scours, the causative pathogen must be eliminated; to combat viral scours, vaccination of cows can protect calves by conferring passive immunity.