Colostrum is breast milk produced after the birth of the newborn and lasts for 2-4 days. Colostrum is very important part of breast milk and lays down the immune system and confers growth factors and other protective factors for the young ones in mammals. This is the source of passive immunity transferred to the baby from the mother. The biological value of bovine colostrum in present day medical practice is documented in clinical trials and large databases containing case reports and anecdotal findings. The main actions include an antibacterial effect and modulation of immune response with the ability to neutralize lipopolysaccharides arising from gram negative bacterial pathogens. It has been found to be effective in infantile hemorrhagic diarrheas, other diarrheas and reduces the likelihood of disease progressing to hemolytic uremic syndrome. It has also been tested in H. pylori infection and diarrhea in immunodeficiency. Side effects of clinical relevance are limited to possible intolerance due to lactose and sensitivity to milk proteins.