Boosting the Immune System: Herbs to Fight Infections

There are a variety of different herbs out there that can help fight viral infections, boost the immune system, and can even be used as flu remedies. They can also have many other health benefits, like supporting digestive and cardiovascular health.  They also a variety of anti-inflammatory compounds. 

With that said, let’s take a look at some effective herbs used to combat viruses, bacteria, and other pathogens.  Bear in mind the exact nutritional composition of each can vary due to the environment and climate they grow in.  In no particular order, let’s get started.


Echinacea is one of the most popular herbs out there, and for good reason!  Echinacea supports immune system function.  There is a good deal of evidence out there to support using Echinacea against viral infections and tumors.  A compound called echinacein inhibits bacteria and viruses from affecting healthy cells, protecting them from ever getting infected in the first place.  Other health benefits from Echinacea include alleviating pain, reducing inflammation, improving skin health, treating upper respiratory issues, and improving mental health.

Studies have found Echinacea is able to reduce the risk of developing a cold by 58% and reducing cold duration 1-4 days.  Another found that Echinacea extracts can slow down tumor growth, inhibiting its ability to spread.  It also has been studied for its anti-inflammatory effects, and has been suggested as a treatment for autoimmune diseases like rheumatoid arthritis, as well as Crohn’s disease, ulcers, and other inflammatory conditions.


Garlic contains two substances, known as allicin and alliin. Both of these are sulfur-containing compounds that have antibiotic properties.  In addition to this, studies have shown garlic has anti-bacterial, anti-fungal, and anti-yeast properties as well.  Some studies suggest garlic can be protective against certain forms of cancer.  Alliin and allicin are thought to prevent the formation of carcinogens in the body and by blocking them from reaching sensitive areas.

Another proposed mechanism is that these two substances inhibit the transformation of healthy cells into cancerous cells. Garlic has also shown the ability to lower low-density lipoprotein (LDL) levels, while raising high-density lipoprotein (HDL) levels.  LDL cholesterol is used to bring fats into your arteries and deliver them for storage in the body, while HDL particles ship them out.

One year-long study on aged garlic (or garlic that has been fermented) showed it can reduce plaque buildup in arteries and also lower levels of homocysteine, which, according to the American Heart Association, is an independent risk factor for heart disease.

Licorice Root

Licorice root, Glycyrrhiza glabra, has been a useful, adaptogenic herb for hundreds of years.  Licorice root can be helpful when combatting heartburn/acid reflux, leaky gut, and improving immune system function.  Licorice has been shown to be effective in aiding against functional dyspepsia (lack of stomach acid), nausea, and indigestion.  A 2010 publication found licorice has antioxidant properties.  This means it can be helpful in providing sore throat relief, and can be used as a natural remedy for coughs.  When searching for a supplement, keep an eye out for deglycyrrhizinated licorice (DGL), as it can be used long-term if needed.

Research shows that licorice is helpful for aiding those who have peptic ulcers, gastritis, or acid reflux (GERD).  Licorice root can also stimulate adrenal gland function, promoting the healthy release of cortisol.  Interestingly enough, some holistic health providers suggest applying licorice to the teeth to kill bacteria and prevent tooth decay.


High quality, professional grade oregano extracts are incredibly powerful and difficult to procure.  Oregano oil has been shown to be as powerful as some antibiotics without the side effects.  Oregano and oregano oil are known to have great amounts of antioxidant, according to studies.  Two powerful compounds found in oregano are carvacrol and thymol, which have powerful antibacterial and antifungal properties. Carvacrol reverses the disease processes of viral infections, allergies, tumors, parasites, and other microbes that can cause inflammation.  In fact, one study showed carvacrol inactivated a norovirus, which can cause stomach pains and diarrhea, within one hour.

One study found oregano oil helped stunt the growth of Escherichia coli and Pseudomonas aeruginosa, two strains of infectious bacteria.  Due to its high antioxidant content, oregano oil has anticancer properties, as another study showed that it can help kill colon cancer cells in humans.  It also has powerful anti-inflammatory effects.  One study found a mixture of oregano and thyme essential oils reduced inflammatory markers in mice suffering from colitis.

  • Olive Leaf

Olive leaf contains compounds that destroy invading organisms and don’t allow viruses to replicate and cause an infection.  This makes it an effective option for the common cold, candida symptoms, meningitis, pneumonia, chronic fatigue syndrome, hepatitis B, malaria, gonorrhea, and tuberculosis.  It has also been used to treat dental, ear, and urinary tract infections.  Olive leaf extracts have been useful to combat a number of bacterial and viral infections.

Olive leaf extract contains the active ingredient oleuropein, which is the compound thought to give olive leaf its antioxidant and anti-inflammatory properties.  Oleuropein has been helpful in lowering blood pressure, improve insulin secretion in diabetics, and support healthy weight management.

Cat’s Claw

Cat’s claw has been around for a long time, more commonly used in South American countries.  It has been used to treat digestive conditions like dysentery, leaky gut syndrome, IBS, colitis, stomach ulcers, fevers, and other conditions like herpes and arthritis.  It also has many anti-inflammatory, antibacterial, antiviral, and antifungal properties. 

Cat’s claw can also help boost immune system function.  One study found that taking 700mg of Cat’s claw for 2 months increased white blood cell counts.  It can also help relieve pain in those with osteoarthritis and rheumatoid arthritis.

Astragalus Root

Astragalus root has been used in Traditional Chinese Medicine for hundreds of years.  Studies have found that astragalus has antiviral properties and can increase immune system function.  Therefore, it can help prevent simple colds and fight the flu virus.  Astragalus also has antibacterial and anti-inflammatory properties, and it is used on the skin for wound care. It is also an adaptogenic herb and can help lower cholesterol levels.

Some of the active compounds found in astragalus root strengthen the immune response and aid in inflammation reduction.  While the research is limited, there are promising results in treating heart conditions, kidney disease, seasonal allergies, chronic fatigue, and more using astragalus root.  Additionally, astragalus has been using to alleviate some pain associated with the side effects of chemotherapy.  It has also been shown to improve kidney function in those diagnoses with kidney infections or proteinuria (protein in the urine). 


Elderberry has been around for centuries.  Almost all parts of the elderberry plant can be used.  The flower, berries, bark, roots, leaves, and juices have been used to treat a variety of health conditions.  Historically, dried berries or elderberry juice has been used to treat influenza, infections, sciatica, headaches, dental pain, heart pain and nerve pain, and as a diuretic.  One study found elderberry could be a viable treatment for influenza types A and B.  Another study found that elderberry extract used within the first 48 hours of the onset of symptoms had reduced flu duration.

Elderberry is high in vitamin C, dietary fiber, flavonoids, phenolic acids, and anthocyanins.  All of these compounds have anti-inflammatory and antioxidant effects.  One study found elderberry reduced the length and severity of the flu. It can also be helpful in fighting harmful bacteria, support the immune system, and even help fight cancer.


Ginger’s health benefits have been known for centuries, and it is a staple of Ayurvedic medicine.  The great part about ginger is that you can easily add it into your cooking! In Ayurvedic medicine, they believe ginger can help break down toxins in organs and act as a cleansing agent for the lymphatic system.  This is what is thought to give ginger its antibacterial, antiviral, and antifungal properties.  Aside from these benefits, ginger can be helpful for alleviating pain and can be used as an anti-nausea remedy. 

Gingerol is the main active compound found in ginger.  It is thought gingerol has powerful anti-inflammatory and antioxidant properties.  Ginger may also improve the day-to-day progression of muscle pain.  Ginger can also be useful in lowering heart disease risk factors, like fasting blood sugar levels and LDL cholesterol levels.


Ginseng is known to help regulate immune system function and fight infections.  Ginseng regulates different types of immune cells, including B-Cells, T-cells, macrophages, natural killer cells, and dendritic cells.  This is important because excessive immune responses are hallmarks of autoimmune conditions.  It also contains antimicrobial compounds, useful for fighting against bacterial and viral infections.  In addition to being a stimulant for the immune system, ginseng also exhibits anti- and chemo-protective effects.

Ginseng has been shown to be helpful in improving brain function, memory, mood, and general behavior.  Ginseng has also been shown to prevent abnormal cell production and growth, meaning it can be a useful as a cancer therapy adjunct.  Panax ginseng also reduced physical and mental fatigue compared to those taking placebo.


Though based in research, personal, and clinical experience, the opinions in this article should not be taken as medical advice. The information is designed for educational purposes only and is not designed to diagnose, treat, or cure disease.  Botanical medicine and nutraceuticals should be treated with the same caution and care as pharmaceuticals, as both have the potential for strong, potentially adverse effects and allergic reactions. Please consult a trained, licensed health care practitioner before proceeding.  Neither the publisher nor the author takes responsibility for possible health consequences of any person reading or following the information in this book. All readers, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition or supplement program.