The amount of iodine consumed by human beings in the United States has increased over the past 10 to 15 years. Although there is no direct evidence of an increased human iodine toxicity problem because of the increased intake, there is some concern that if this trend continues, the greater iodine concentration may contribute to an increase in thyroid disorders. Because iodine content in milk has increased by 300% to 500% over the past 10 to 15 years, factors contributing to this increase have been studied. Organic iodine additions to the feed supply have contributed to large increases in iodine content in milk from some farms, and are considered the main factor contributing to the large increase in iodine content in milk values. Iodine teat dips and udder washes contribute to the increased iodine content of milk but generally do not result in increases of more than 150 micrograms/L. Iodine-sanitizing agents used on milking equipment or in milk transfer and storage equipment can contribute large amounts if improperly used, but the frequency of this problem is small. Iodine content in meat does increase with increased iodine intake, but the transfer of iodine to meat is relatively lower than it is to milk.