If you’ve stared down the ever-expanding wall of herbal supplements at your local health food store lately, you know that trying to find the ones that are the best fit for you can be overwhelming. And unfortunately, it’s not as simple as pairing one symptom with one plant.
“It’s hard to divide herbs into separate categories of benefits, as most of them share many of the same attributes,” says Bill Rawls, MD, medical director of Vital Plan. “For instance, plenty of herbs help balance the microflora in the gut microbiome or provide support for the immune system.” That being said, some are better known for certain properties over others.
Here, Dr. Rawls shares five herbal categories you should know before you go so you can shop wisely—and feel the benefits sooner.
Your body is loaded with microbes—everyone’s is. “We now think there are more than 40,000 types of microbes in our gut,” says Dr. Rawls. Some, like the good bacteria that line your GI tract, help to support your immune system and digestion. But others—viruses, bad bacteria, parasites—can make you ill, disrupt your body’s natural rhythms, and in general make all your parts run less effectively.
Plants have to deal with microbial problems, too. But instead of an immune system, plants use a spectrum of biochemicals to help suppress the everyday microbial threats they encounter and encourage the growth of good microbes.
“It’s so complex that it’s beyond our complete understanding,” says Dr. Rawls. “I look at it as a natural intelligence that’s inherent in the plant—the product of millions of years of dealing with a problem, and through trial and error, learning how to best overcome it.”
We do know that certain herbs have stronger antimicrobial properties than others—if only because we’ve thought to test them in labs. “Scientists have generally studied herbs that were traditionally used for conditions we now know to be infectious, such as bronchitis and bladder infections,” says Dr. Rawls.
Here are some of the top antimicrobial herbs we know most about:
This phytonutrient is found in certain herbs and foods such as grapes, berries, and peanuts. It’s part of a group of compounds called polyphenols, a type of antioxidant that helps protect your body against cellular damage.
Some research suggests resveratrol has antibacterial properties and may also help promote good gut bacteria. For instance, a study in the journal Food & Function found that in mice fed a high-fat diet, resveratrol helped inhibit the growth of “bad” bacteria and increase the growth of Lactobacillus and Bifidobacterium, “good” bacteria.
“Resveratrol is produced by several plants in response to attack or injury,” explains Dr. Rawls, and its reparative properties are passed on to us through consumption. One particularly good source is Japanese knotweed, a plant which contains high concentrations of trans-resveratrol, the active form of the compound most useful to the body.
This herb has long been a staple in India and China for aiding the immune system in the face of acute upper respiratory illnesses such as cough, cold, and flu. “It was used widely in India during the flu of 1918, and was credited as one of the reasons why that country had such a low death rate,” says Dr. Rawls.
More recently, research supports its cold-fighting abilities. In one research review published last year in the medical journal PLOS, study authors found that andrographis shortened the duration of cough, sore throat, and sick leave when compared to usual care.
This woody vine has been used for thousands of years in the Amazon to support a healthy immune system and fight infection. It’s thought that certain compounds in cat’s claw (known as oxindole alkaloids) help promote healthy immune function and also act as an antioxidant, which is a substance that helps protect the body from free radicals and inflammation.
Indeed, a number of studies point to the anti-inflammatory benefits of cat’s claw, including one published in the journal Alimentary Pharmacology & Therapeutics. It found that the herb helped protect cells against oxidative stress—cell damage caused by biological pressures such as exposure to toxins or illnesses like bacterial or viral infection—and inhibit the activation of NF-kappaB, proteins that play a central role in inflammation.
A staple of traditional Chinese medicine, this herb has a long history of use for supporting the immune system against infection, allergies, inflammation, and even cancer. It contains flavones, compounds well known for their beneficial antiviral and anti-oxidant effects.
In promising research on Chinese skullcap in the journal Science Advances, scientists isolated unique flavones called wagonin and baicalein that helped kill cancer cells in both test tube and animal studies. It’s important to note Chinese skullcap is not the same as American skullcap, which is usually used to support the body against neurologic disorders such as Alzheimer’s, Parkinson’s, and depression.
The main benefits of this tasty bulb comes from allicin—the same compound that gives garlic its potent smell. It’s difficult to get enough allicin from food sources, however, since most of it is lost when garlic is crushed or cooked, so supplementation is key.
Allicin’s antimicrobial properties are well supported by research. For instance, allicin was found to help combat a wide range of bacteria (including E. coli), fungi (particularly Candida albicans), parasites, and viruses in a study published in Microbes & Infection. It appears to work by both inhibiting the proliferation of bacterial, fungal, and cancer cells and even killing them outright, a research review in the journal Molecules suggests.
These herbs help your body adapt to the negative effects of stress by acting on the hypothalamus, the region of the brain that manages our stress response.
“When we’re overstressed, it causes the hypothalamus to push our adrenal glands too hard,” explains Dr. Rawls. “In turn, the adrenals pump out excessive levels of the stress hormone cortisol.” Over time, chronically elevated stress hormones can increase the risk for inflammation, impaired immune function, hypertension, and more.
Adaptogenic herbs have chemical substances that send feedback to the hypothalamus, telling it to calm down when it’s in overdrive, or turn up if it’s a bit sluggish. “Because of adaptogens’ spectrum of chemicals, they tend to have a normalizing effect,” says Dr. Rawls. “They’re defined as an amphoteric — something that brings things back to center.” Here, some of his go-to adaptogens:
This rare mushroom was originally discovered growing on Tibetan caterpillars (there are now alternative, vegan methods). It was traditionally reserved for Chinese emperors and royalty. It’s so revered that it was allegedly touted as the magic mushroom behind the world record breaking success of Chinese athletes at the 1993 National Chinese Olympic games in Beijing.
“Cordyceps has been found to enhance aerobic exercise, which isn’t surprising when you consider it was traditionally taken to improve work tolerance at high altitudes,” says Dr. Rawls. One study in the Chinese Journal of Integrated Medicine found that people who took cordyceps daily for six weeks had increased VO2 max (maximum oxygen uptake, a measure of ability to perform sustained activity) and less fatigue during exercise compared to those taking a placebo.
This medicinal mushroom has been used in traditional Chinese medicine for more than 2,000 years, and its Chinese name, ling zhi, translates as “the herb of spiritual potency.” “Reishi is believed to support the immune system and promote calm,” explains Dr. Rawls. It’s often combined with cordyceps for a double dose of serenity.
Reishi’s adaptogenic benefits are mild and cumulative, and research has shown that it’s both safe and effective to take long term. It’s been linked with relieving stress, altitude sickness, inflammation, and neurasthenia, a condition characterized by extreme fatigue, headache, and irritability. In a study of patients with neurasthenia, those who took reishi daily experienced significantly less fatigue and an increased sense of well-being after eight weeks.
Also known as “Siberian ginseng,” this energizing adaptogen has been used for thousands of years in Eastern Asia and Russia. “Workers and athletes in these countries have used eleuthero to enhance their stamina, and research has found that it improves the ability of people to stay up later, work harder, help the body adjust to altitude, and even perform better athletically,” notes Dr. Rawls.
Beyond its energizing capabilities, eleuthero seems particularly helpful in easing stress and stress-related side effects. Healthy, young men and women in one study experienced a significant reduction in stress-related high blood pressure, whereas a placebo had no effect. And an interesting, second study found that eleuthero helped enhance short-term memory in healthy adults— especially those who were more nervous and sensitive to stress.
Carminatives are a smart go-to for those experiencing gastrointestinal distress. “They calm the digestive system and act like a buffer, helping to relieve painful spasms,” explains Dr. Rawls. They also help reduce inflammation and eliminate gas from the digestive tract. The credit goes to carminatives’ volatile oils, which have anti-inflammatory and antispasmodic effects on the mucus lining and muscles of the GI tract.
Carminatives are mostly helpful for counteracting the negative effects of bad dietary habits, such as eating too many carbohydrates and processed foods, which can result in bacterial overgrowth and disrupted digestion. “Ideally, you don’t need to take carminatives for too long,” says Dr. Rawls. “A better idea is to change your diet and eat right so you don’t have problems in the first place.”
Dr. Rawls points to cardamom, an antispasmodic that helps relieve uncomfortable stomach contractions, and fennel, which relaxes the smooth muscles of your digestive system to help ease constipation and usher food through your GI tract. Other common carminatives include lemon balm, peppermint, parsley, aniseed, sage, and thyme.
A nervine is something that restores or soothes the nervous system when you’re stressed or anxious. They act like neurotransmitters, brain chemicals that transport critical information throughout the brain and body, explains Dr. Rawls. “Nervines probably effect multiple neurotransmitters, the main one being GABA, a calming neurotransmitter that helps control fear and anxiety.”
Dr. Rawls warns that you have to be careful with nervines, because they have more of a drug-like effect than any of the herbal categories mentioned above, so there’s a low risk of developing tolerance or even slight dependence over time. Three nervines he recommends include:
Found in the depths of the Amazon, passion flower elicits calm and is often used as a sleep aid to support a good night’s rest without the next-morning grogginess. Participants in one study who sipped a cup of passion flower tea each day for a week reported better sleep quality than those drinking a placebo tea.
Passion flower is also often touted for its anxiety relieving benefits. For instance, preliminary research published in Cochrane Database Systematic Reviews suggests the herb is as effective at easing anxiety symptoms as prescription benzodiazepines, although the study authors noted that more research is needed. And as Dr. Rawls reminds, take them with care — and in tandem with making lifestyle changes for alleviating agitation and worry.
Native to India, bacopa is a nervine tonic, a category of nervines that helps restore and strengthen damaged nervous tissue caused by pathology or physical trauma. Bacopa has been used for thousands of years to nourish the nervous system, promote calm, and reduce anxiety. It’s also been studied for supporting cognitive function.
This central Eurasian herb has been long used to reduce stress and anxiety, and supposedly got its name for aiding in menstrual and uterine conditions. It’s known to help stimulate menstruation that’s been delayed, particularly by anxiety or tension. Motherwort is also considered a heart tonic for its ability to ease anxiety-induced heart palpitations. But it may interfere with heart medications, so talk to your health practitioner before taking it if you have any cardiovascular concerns, and avoid it if you’re pregnant.
We all have a natural mucinous lining in our gut that helps block things that can be damaging to our cells, such as bad bacteria or high levels of certain food compounds like lectins, oxalates, and gluten. But that layer can get stripped away by various types of gut dysfunction. That’s where demulcents come in.
“Demulcents contain a slick, gel-like substance called mucilage that’s similar to our natural gut lining, says Dr. Rawls. “They help to recreate that barrier to protect the cells that line the gut.” Demulcents also soothe the tissues of the gut lining, which is great if they’re sensitive or inflamed, as well as the intestinal lining, which can help ease diarrhea. Two that Dr. Rawls recommends are slippery elm and, believe it or not, marshmallow.
“Marshmallows were not always a candy,” says Dr. Rawls. “The roots of the marshmallow plant are high in mucilage, and people used to take it to protect their gut. Over time, they started putting a little sugar in it so it would taste good, and before long it became these puffy gelatin sugary things that had no marshmallow plant at all.”
This list is by no means conclusive—remember, numerous herbs share beneficial properties, and the list of herbs with science-backed benefits is growing every day. But using these categories as a starting point to pull together your ideal protocol will help you narrow your options and discover what works best for you.
Discover more in Dr. Bill Rawls' new #1 Bestselling book: The Cellular Wellness Solution: Tap Into Your Full Health Potential with the Science-Backed Power of Herbs.