Between the stress of travel, compromised sleep schedules, holiday indulgences, and exposure to the coughing, sneezing crush of fellow travelers, it can be a challenge to get to a family get-together without picking up some unwanted baggage along the way. Here's how to boost your odds of beating holiday bugs by revving up your immune system, starting about a week before you break out the Samsonite.

Before you go

  • Choose foods rich in beta-glucan (such as oats, barley, and the mushrooms shiitake, reishi, and maitake), or look for a dietary supplement of beta-glucan (take 200–800 mg daily), which provides a strong boost to the immune system, enhancing resistance to viruses and bacteria. Beta-glucan, a fiberlike complex sugar, amplifies activity of specialized immune cells called phagocytes that engulf and destroy germs.
  • Fortify defenses with eleuthero (Eleutherococcus senticosus). Also known as Siberian ginseng, eleuthero boosts immunity while giving you an edge on handling stress—and who doesn't need that during the holidays? Eleuthero also ups white blood cell counts, so your body is better able to fight off any of the germs you may encounter.
  • Add andrographis. Eleuthero taken in combination with the herb andrographis (Andrographis paniculata) provides a one-two punch that knocks out colds and the flu. Andrographis (sometimes called "Indian echinacea") is a mainstay of both Ayurvedic and Traditional Chinese Medicine. In two studies involving almost 900 cold- and flu-sufferers, taking andrographis, or a combination of the herb with Siberian ginseng, eased cold and flu symptoms and even helped prevent these illnesses from taking hold in the first place.

En Route

  • Be happy. Sure, you could wear a mask while sitting on the airplane, but you'll be even better protected against cold germs (and avoid strange looks from fellow passengers) if you simply maintain an easygoing, lighthearted attitude. A recent study performed at Carnegie Mellon University found that people who have a positive outlook are less likely to get sick. Even when folks are exposed to common cold and influenza viruses, those with more cheery dispositions are less likely to actually develop an illness. So do yourself a favor and don't get wound up when the flight is delayed. Instead, take a deep breath and find something to laugh about. If it's a comedy, watch the in-flight movie, or tune in to upbeat music.
  • Stay hydrated. You've heard it before, and here's why: When mucous membranes are moist, they physically block the entrance of viruses through the nose, eyes, or mouth. So drink up! Aim for eight 8-ounce glasses of low-sugar, caffeine-free beverages each travel day. Consider packing along individual vitamin-boost drink packets or tea bags (bonus points for immune-boosting green tea) to jazz up your water—and your immune system.
  • Calm nerves. If travel makes you feel a bit unsettled (which in turn dampens your body's germ-fighting abilities), then pack flower essences to calm yourself and keep your immune defenses on their game. "Flower essences are botanical medicines made from flowers and preserved in a liquid or cream form; they are gentle in their ability to help shift your emotions," says Laurie Steelsmith, ND, LAc, author of Natural Choices for Women's Health (Three Rivers/Random House, 2005). Take Bach Rescue Remedy, a combination of five flower essences renowned for their calming effect, orally as a liquid (just a few drops should suffice).

After Arrival

  • Get more z's. When you finally make it to your destination, it may be hard to get a good night's sleep. To help adjust to a new bed—and perhaps a new time zone—try L-theanine, an amino acid found in green tea, which calms the body and strengthens immunity. L-theanine interacts with brain receptors associated with relaxation to help you unwind and fall asleep. It can also be used for "night-before" trip jitters. Take 200 mg an hour before bedtime.
  • Boost with beneficial bacteria. In addition to protecting your gut from any harmful bacteria that you may come into contact with, "probiotics can help your digestive system deal with changes in diet," says Steelsmith. In fact, taking probiotics may help shorten the length and severity of any illness you pick up. Choose a product that contains both Lactobacillus acidophilus and Bifidobacterium, that doesn't require refrigeration, and that guarantees viability of its friendly bugs. Take 1–2 billion colony-forming units a day.
  • Maintain a lighthearted attitude. People who have a positive outlook are less likely to get sick

Oregon-based freelancer Victoria Dolby Toews, MPH, once made it through four consecutive winters cold-free with the help of dietary supplements. Even now, as the mother of young kids, she avoids about half the colds of the average American.