The Reference Guide
Tried, traditional and tested: every remedy in our library, ranked honestly by how much evidence stands behind it.
How we rank evidence
Studied in people: NIH's National Center for Complementary and Integrative Health (NCCIH) summarizes human studies pointing to a possible benefit for one specific use. Traditional + some evidence: centuries of use, but human research is small, mixed or early. Traditional use: a time-honored kitchen or folk herb with little clinical research. None of these tiers means a plant treats, cures or prevents any disease.
Studied in people Studied in people
Human studies summarized by NIH NCCIH suggest a possible benefit for a specific use.
| Herb | What it's known for | Key safety note |
|---|---|---|
| Ginger | NCCIH summarizes human studies suggesting ginger may help relieve nausea and vomiting associated with pregnancy; findings for other kinds of nausea are mixed. | Generally considered safe in food amounts |
| Peppermint | NCCIH reports that enteric-coated peppermint oil capsules may help relieve symptoms of irritable bowel syndrome in some people, based on a number of human studies. Evidence for other uses is limited. | Peppermint oil can cause heartburn; avoid if you have reflux |
| Garlic | NCCIH notes some evidence that garlic may slightly lower blood pressure and cholesterol in some people, though study results vary. It is not a substitute for care from your doctor. | Can cause bad breath, heartburn and upset stomach |
| Cranberry | NCCIH reports that cranberry products may help reduce the risk of repeat urinary tract infections in some groups, such as women with recurring UTIs, but they are not a treatment for an active infection. | Large amounts of juice can cause stomach upset and add sugar |
| Green Tea | NCCIH notes that green tea's caffeine supports alertness. Research on other possible benefits is ongoing and results are mixed. | Contains caffeine; limit if pregnant or sensitive |
| Flaxseed | NCCIH notes that ground flaxseed contains soluble fiber and may help with constipation, and studies have looked at its effects on cholesterol and blood sugar with mixed results. | Drink plenty of water with flaxseed |
Traditional + some evidence Traditional + some evidence
Long traditional use; human research is limited, small or mixed.
| Herb | What it's known for | Key safety note |
|---|---|---|
| Turmeric | NCCIH reports that turmeric and its compound curcumin have been studied for many conditions, but strong conclusions can't yet be drawn; curcumin is poorly absorbed on its own. | Usually safe in food amounts |
| Chamomile | NCCIH notes that chamomile has been studied for sleep and anxiety, but the research is limited and not conclusive. | People allergic to ragweed, daisies or related plants may react |
| Echinacea | NCCIH reports that some studies suggest echinacea may slightly reduce the chance of catching a cold, but evidence that it shortens colds is weak. | May cause allergic reactions, especially in people allergic to daisy-family plants |
| Elderberry | NCCIH notes some small studies on elderberry and flu-like symptoms, but the evidence is limited and not definitive. | Raw or unripe berries, leaves and stems can cause nausea, vomiting and diarrhea |
| Lavender | NCCIH reports some research on oral lavender oil and lavender aromatherapy for anxiety, but more rigorous studies are needed. | Topical use may irritate skin |
| Cinnamon | NCCIH reports that studies of cinnamon and blood sugar have had mixed results, and cinnamon has not been shown to help any health condition conclusively. | Cassia cinnamon contains coumarin, which in large amounts may harm the liver |
| Fenugreek | NCCIH reports that some research on fenugreek and blood sugar shows small effects, but the evidence is limited. | Should not be used in pregnancy in amounts above food |
| Ashwagandha | NCCIH reports a number of small studies on ashwagandha for stress and sleep with some positive results, but long-term safety is not well understood. | Rare liver injury has been reported |
| Milk Thistle | NCCIH notes that milk thistle has been studied for liver conditions, but results are mixed and no strong conclusions have been reached. | Generally well tolerated; may cause digestive upset |
| Sage | NCCIH notes small studies on sage for memory and hot flashes, but there isn't enough evidence to draw conclusions. | Food amounts are safe |
| Licorice Root | NCCIH reports that there isn't enough research to know whether licorice helps any health condition, and that too much can be harmful. | Large amounts or long-term use can raise blood pressure and lower potassium |
| Asian Ginseng | NCCIH notes some studies on ginseng for blood sugar and thinking, but results are not consistent. | Short-term use appears safe for most adults; may cause headache and sleep trouble |
| Aloe Vera | NCCIH notes some evidence that topical aloe gel may help with certain skin conditions, but oral aloe latex is not considered safe. | Topical gel is usually well tolerated |
Traditional use Traditional use
Traditional and culinary use; little or no clinical research.
| Herb | What it's known for | Key safety note |
|---|---|---|
| Dandelion | NCCIH reports there is no compelling scientific evidence for using dandelion for any health purpose; it is mostly studied in the lab. | May cause allergic reactions in people sensitive to daisy-family plants |
| Rosemary | Rosemary has been studied mostly in the lab and in small human trials; there is not enough evidence to support health uses. | Food amounts are safe |
| Thyme | Thyme has been included in some combination cough-syrup studies in Europe, but evidence for thyme alone is limited. | Food amounts are safe |
| Cumin | A few small human studies have looked at cumin, but there is not enough evidence to support health uses. | Food amounts are generally safe |
| Coriander & Cilantro | Coriander has been studied mostly in the lab and animals; human evidence is limited. | Food amounts are safe |
Before you begin
Natural doesn't always mean safe for everyone. Herbs can interact with medicines like blood thinners, diabetes drugs and sedatives. Bring this list to your doctor or pharmacist. The NIH Office of Dietary Supplements and NCCIH's guide to using supplements wisely are good places to start.