Complementary and Alternative Medicine Therapies for Cold and Flu Season: What Is the Science?

Kathi J. Kemper, MD, MPH


November 03, 2009


Influenza-like illnesses (ILI) and upper respiratory tract infections (URTI) typically peak in prevalence in the late fall through early spring. The media extol the benefits of good hygiene and immunizations, echoing the advice of healthcare professionals. In addition, home remedies and natural products have long been used to prevent and treat common viral illnesses. How should clinicians advise patients about the effectiveness and safety of these remedies when used to enhance immune function to prevent or treat virally mediated ILI or URTI?

Home Remedies

Home remedies range from diet (chicken soup or garlic) and dressing (warm head and feet) to poultices and vaporizers. Culturally, some families avoid cold foods (including dairy) and encourage spicy foods (such as garlic and ginger). Hot tea with honey and lemon is another popular remedy during winter months. Some mothers rub salves containing menthol, thyme, or eucalyptus on the sick family member's chest, and others make mustard poultices or enforce wearing hats, scarves, or warm socks. Hot steam or cool mist vaporizers are commonly used to increase household humidity and soothe dry respiratory passages; neti pots (small vessels with long narrow spouts) and saline rinses are used to wash viruses, allergens, and mucus out of the nose. Whether home remedies are effective prophylactic or therapeutic agents, or just make patients feel better to use them, these practices are generally safe and support cultural identity and self-efficacy, and their use can be tolerated by healthcare providers.[1]

Sleep and Fluids

"Drink plenty of fluids" is well-worn advice that may have a basis in its common sense consequences. Dehydration can dry the respiratory mucosal surfaces; however, there is little evidence that drowning in extra fluids improves resistance to viral infections. On the other hand, the frequent trips to the restroom necessitated by larger than usual intake of fluids may promote additional hand washing, thereby reducing the spread of infections.

"Get plenty of sleep" is another adage voiced by grandmothers as well as clinicians, with the intent of supporting immune function. Sleep deprivation is associated with disruptions of immune function.[2] In laboratory studies, depriving healthy adults of sleep induces a significant increase in both pro-inflammatory and anti-inflammatory markers (ie, E-selectin, intracellular adhesion molecule-1, interleukin [IL]-1beta, and IL-1 receptor antagonist) and a significant decrease in C-reactive protein and IL-6.[3] Sleep deprivation can also impair the immune response to influenza vaccine. In a study of adult volunteers, influenza immunizations were administered to one group after 4 nights of partial sleep deprivation (sleep restricted to 4 hours per night) and to a second group after 4 full nights (7.5-8.5 hours per night) of sleep. Ten days after vaccination, mean antibody titers in the sleep-deprived volunteers were less than half of those in the volunteers who had normal sleep durations.[4] Because individuals with poorer responses to vaccines also experience higher rates of illness, these findings support the concept that adequate amounts of sleep are important for optimal immunity during respiratory illness seasons. There are no data to suggest that excessive sleep (more than 10-12 hours per night for adolescents and adults) further improves immune function, but it appears prudent to avoid sleep deficits.

Jessica is wise to ensure that those in her family practice good hygiene, maintain good hydration, avoid sleep deficit, and receive immunizations.


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