In a previous edition, we discussed why antibiotic resistance and the use of antibiotics in swine diets are considered to be problematic. An obvious question then is to look at what actually happens when antibiotics are withdrawn from swine diets. In this edition we will look at whether this is necessarily a good thing and whether we create any unintended consequences when we do this. The economic benefits of including antibiotics in swine diets are clear; this is the main reason why producers include antibiotics in swine diets. Data collected from over 1,000 experiments in the United States from 1950 to 1985 showed an increase in growth rate and feed efficiency in all phases of growth; with the greatest increase in young pigs. Growth rate increased by 16.4% during the starting phase (7-25 kg ), 10.6% during the growing phase (17-49 kg), and 4.2% during the grow-finish phase (24-89 kg). Likewise, feed efficiency increase by 6.9%, 4.5% and 2.2% during the starting phase, growing phase and growing-finishing phase, respectively. When antibiotics are taken out of swine diets there has been a dramatic decrease in antibiotic resistant microorgansisms isolated from swine. But there has not necessarily been a similar decrease in antibiotic resistant bacteria of the same species and for the same antibiotic in humans. This means that bacteria isolated from hospital setting were still resistant to an antibiotic that was withdrawn from swine diets. The reason for this is not well understood but is probably the result of co-selection of the antibiotic resistant organism by some other mechanism. However, studies done in Germany, The Netherlands, and Italy, have demonstrated a significant decline in antibiotic resistant bacteria in hospital settings after specific antibiotics have been banned in food animals. Here in Manitoba we need to be investigating scientifically based alternatives. In the next issue we will look at what these alternatives are.