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Chapter 2 The Pre-Travel Consultation Counseling & Advice for Travelers

Discussing Complementary or Alternative Health Approaches with Travelers

Catherine Law, Tina Adler, Jack Killen

Travelers often ask their health care providers about the use of complementary or alternative health approaches for travel-related illnesses and conditions. This should come as no surprise, given that many people—approximately 1 in 3 Americans—report using products or practices that have origins outside of conventional medicine to complement treatment for a variety of medical conditions or to promote general wellness. Some of these approaches for travel-related health problems are widely promoted in advertising or discussed on the Internet. However, little of this information is supported by research evidence, and some of it is misleading or false. This section focuses on what the research says about some of the herbal remedies, dietary supplements, and other complementary health approaches frequently suggested for travel-related ailments.


Malaria Prophylaxis and Treatment

Artemisia (Artemisia annua L. or sweet wormwood)

Artemisinin-containing therapies, such as artemether-lumefantrine and artesunate, are pharmaceutical drugs and drug combinations originally derived from the herbal medicine Artemisia and are now a standard treatment for malaria in most of the world. Consumer websites and news stories have claimed that using the herb Artemisia alone may prevent malaria, but studies show that it does not. The World Health Organization does not recommend using Artemisia plant material in any form (including tea) for treating or preventing malaria. Recommended drugs used to prevent and treat malaria are described in Chapter 3, Malaria.

Vitamin A

Limited research suggests that when children with malaria are deficient in vitamin A, supplements may help lower their fever and blood levels of the parasite that causes malaria. However, there is no evidence that vitamin A prevents malaria. Vitamin A is fat soluble, and large or frequent doses of vitamin A may accumulate in the body and cause acute or chronic toxicity. High intakes of vitamin A have been linked to birth defects. Taking beta-carotene has been linked to an increased risk of lung cancer and cardiovascular disease in some smokers.

Travelers’ Diarrhea Prevention and Treatment


Probiotics are often suggested to help prevent travelers’ diarrhea (TD). Research on their use in treating acute infectious diarrhea is generally positive. Results from studies on preventing TD are mixed but encouraging. Given current data, it must be assumed that effects of probiotics in any given study are specific to the strain or strains tested. The Food and Drug Administration (FDA) has not approved any health claims for probiotics.

In healthy people, probiotics usually have only minor side effects, if any. For more information see Nonantimicrobial Drugs for Prophylaxis in the Travelers’ Diarrhea section earlier in this chapter.


Goldenseal is a perennial herb that has been touted as treatment for a variety of ailments. No high-quality research on goldenseal for TD has been conducted. Studies show that goldenseal inhibits cytochrome P450 2D6, raising concerns that it may increase the toxicity or alter the effects of many commonly used drugs.

Activated charcoal

There is no solid evidence that activated charcoal helps with TD, bloating, stomach cramps, or gas. The side effects of activated charcoal have not been well documented but were mild when tested on healthy people. Warning: Children should not be given activated charcoal for diarrhea and dehydration. It may absorb nutrients, enzymes, and antibiotics in the intestine and mask the severity of fluid loss.

Grapefruit seed extract

Despite claims that grapefruit seed extract prevents bacterial foodborne illnesses if taken daily, there are no published clinical trial data on its effectiveness or safety for TD.

Altitude Illness Prevention and Treatment

There is little, if any, evidence that dietary or herbal supplements help prevent or treat altitude illness (often referred to as mountain sickness).


Coca tea has been used for altitude illness, but there is no strong evidence on whether it works or has adverse effects. It will result in a positive drug test for cocaine metabolites. For more information see Chapter 4, Peru: Cusco–Machu Picchu.


There is no evidence supporting claims that garlic helps reduce altitude illness.

Garlic supplements appear safe for most adults but may reduce blood clotting and interfere with the effectiveness of the HIV drug saquinavir.

Ginkgo biloba

Results from several small studies of ginkgo for preventing altitude illness show conflicting, but mostly negative, results. Whether these differences relate to the different preparations used in these studies cannot be determined. Products made from standardized ginkgo leaf extracts appear to be safe when used appropriately. However, National Toxicology Program studies showed that rodents developed tumors after being given a ginkgo extract for up to 2 years.

Vitamin E

Only one small study has investigated vitamin E, in combination with other antioxidants, for altitude illness, and the results were negative. Vitamin E supplements have been linked to an increased risk of hemorrhagic stroke. They also have the potential to interact with several types of medications, including statins, niacin, and warfarin.

Motion Sickness Prevention and Treatment

Acupressure and/or magnets

Using acupressure is advocated by some to prevent or treat motion sickness. Results of studies to date are mixed. There are no published data to support use of magnets, alone or in combination with acupressure.


Studies are conflicting on whether ginger is effective for motion sickness. Based on the research to date, ginger is probably safe but may interact with many medications. The effect of using ginger supplements with common over-the-counter drugs for motion sickness (such as dimenhydrinate [Dramamine]) is unknown.

Other dietary supplements or products

There is no evidence supporting claims that vitamin B6 and homeopathic products prevent or alleviate motion sickness. Excessive use of vitamin B6 supplements can affect nerve function.

Jet Lag/Sleep


Melatonin supplements may help with sleep problems caused by jet lag. In a 2007 clinical practice guideline, the American Academy of Sleep Medicine supported using melatonin to reduce jet lag symptoms and improve sleep after traveling across >1 time zone. In a 2009 systematic review, results from six small studies and two large studies suggested that melatonin may ease jet lag. Taking between 0.5 and 5 mg melatonin appears to be effective. Before recommending melatonin, consider the following:

  • People with epilepsy or who take an oral anticoagulant should not use melatonin without medical supervision.
  • Melatonin supplements appear to be safe for most people when used short-term; less is known about its long-term safety.
  • Melatonin should not be taken early in the day, as it may cause sleepiness and delay adaptation to local time.
  • The amount of melatonin in products and the dosages recommended on labels can vary.
  • Side effects from melatonin are uncommon but can include drowsiness, headache, dizziness, or nausea.

See the Jet Lag section earlier in this chapter for more information.

Relaxation techniques

Relaxation techniques, such as progressive relaxation and mindfulness-based stress reduction, may help with insomnia, but it has not been established whether they are effective for jet lag.

Other herbal or dietary supplements

There is very little evidence that aromatherapy, chamomile, or valerian helps with insomnia. None have substantial side effects, but chamomile can cause allergic reactions. Kava is also advertised for sleep, but good research on kava for insomnia is lacking. More importantly, kava supplements have been linked to a risk of severe liver damage.

Colds and Influenza

Zinc supplements taken orally may reduce the length and severity of a cold. Zinc, particularly in large doses, can have side effects, including nausea and diarrhea. The intranasal use of zinc can cause anosmia (loss of sense of smell), which may be long lasting or permanent. In 2009, FDA warned consumers to stop using several intranasal zinc products because they had been linked to cases of anosmia.

Nasal saline irrigation, such as with neti pots, may be useful and safe for chronic sinusitis as long as sterile or distilled water is used. There is little research to support using nasal saline irrigation for acute upper respiratory infections.

Taking vitamin C supplements regularly may slightly reduce the length and severity of colds but does not reduce the number of colds. Even at high doses, vitamin C supplements appear safe.

There is no strong evidence to support claims promoting echinacea, probiotics, or the homeopathic product Oscillococcinum for flu.

There is no good evidence that Chinese herbs, oil of oregano, or eucalyptus essential oil prevents or treats colds and other infections.

Other Common or Travel-Related Infections

Hepatitis C

Medicinal herbs should not be used for treatment of hepatitis C outside of well-designed, randomized clinical trials. A recently published randomized clinical trial found no evidence of benefit from silymarin (an extract from milk thistle seeds) in patients with advanced hepatitis C. In addition, a systematic review of 10 randomized clinical trials found no firm evidence of efficacy of any medicinal herbs for hepatitis C virus infection. Two of the trials studied a single herb or herbal ingredient; the others studied different compounds of herbs.

Vaginal infections

Probiotics have been studied for treating vaginal infections, but there is not enough supporting evidence to suggest that they are helpful.

Box 2-08. About dietary supplements and unproven therapies

  • The Food and Drug Administration (FDA) regulates dietary supplements, but regulations for dietary supplements are different and generally less strict than those for prescription or over-the-counter drugs. Learn more at
  • Two major safety concerns about dietary supplements are potential drug interactions and product contamination. Analyses of supplements sometimes find differences between labeled and actual ingredients. For example, an herbal supplement may not contain the correct plant species or the amounts of the ingredients may be lower or higher than the label states.
  • Consult the FDA’s safety advisories to learn the latest regarding product recalls and safety alerts at
  • Unproven therapies are discussed in this section only for educational purposes and are not recommended for use. The Centers for Disease Control and Prevention (CDC) endorses only FDA-approved therapies.


Laboratory-based studies found that botanicals, including citronella products, worked for shorter periods than products containing DEET. In addition to DEET products, CDC recommends products containing oil of lemon eucalyptus (OLE), such as the products Repel and Off! Botanicals.

There are no high-quality studies on the effectiveness or safety for people of neem oil, which is used in agricultural insecticide products and promoted on some websites for human use.


There is no credible scientific evidence, nor any plausible scientific rationale, to support claims that certain homeopathic products (sometimes called nosodes or homeopathic immunizations) are effective substitutes for conventional immunizations. For more information see General Recommendations for Vaccination & Immunoprophylaxis in this chapter.


CDC does not recommend traveling to other countries for untested medical interventions or to buy medications that are not approved in the United States.


Given the vast number of complementary or alternative interventions and the wealth of potentially misleading information about them that can be found on the Internet, discussing the use of these approaches with patients may seem daunting. However, it is important to be proactive, as surveys show that many patients are reluctant to raise the topic with their health care providers. Federal agencies, such as the National Center for Complementary and Integrative Health (NCCIH), offer evidence-based resources ( to help you and your patients have a meaningful discussion about complementary approaches.


The authors thank Dr. John Williamson of NCCIH for his scientific review and Ms. Karen Kaplan and Ms. Patricia Andersen of Westat for their editorial assistance.


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