In response to the current confirmed human outbreaks of influenza A (H1N1) in the United States of America and Mexico, the Taiwan Centers for Disease Control (Taiwan CDC) has followed other countries’ steps in increasing the level of warning against travel to Mexico because regional outbreaks have occurred there. On the other hand, limited clusters of cases have occurred in California and Texas in the United States.Travelers are urged to reinforce prevention measures before and after the trip to areas affected by the outbreak.Taiwan CDC stays in constant touch with the World Health Organization through the IHR Focal Point and will increase the level of travel warning again, recommending against all non-essential travels to the affected areas, when necessary.For more information about influenza A (H1N1), please visit the Taiwan CDC web site at http://www.cdc.gov.tw.