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Pop a Probiotic
"About 70 percent of your immune system is in your gut, so I always take probiotics with me when I travel," says Frank Lipman, MD, founder and director of the Eleven Eleven Wellness Center in New York City. He recommends pills that contain lactobacilli and bifidobacteria with a total of at least 30 billion units (most products include this info on the label). Both strains may help prevent G.I. disorders.