The goals of our study are to critically evaluate if a healthy population supplemented with Transfer factor experiences fewer incidences of colds and flu, or experience shorter duration of illness compared to an identical population taking placebo. In this study we will give either Transfer factor or a placebo to two groups of healthy adult men and women for a period of 7 weeks in a double-blind experimental design. The frequency and duration of colds and flu-like symptoms will be recorded during the course of the study. Saliva samples will be collected weekly and assessed for salivary IgA secretion rate. Data from this study will establish the efficacy of Transfer Factor to support a healthy immune system.