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A Guide to Common Medicinal Herbs

For thousands of years, people have used herbs as medicine all over the world. In the U.S., the FDA controls the safe use of herbal supplements. But they are not as strictly controlled as prescription medicines.

It's important to understand the herbs you're using. The quality of herbs also matters. Some companies add fillers. This helps to make their herbal supplements cheaper. But they may not work as well. Or they may cause side effects. Even if something is natural, it may not be safe.

Below are common herbal medicines that research has shown to be safe and work when used right. Always tell your healthcare providers if you use any herbs or supplements. They need to know if they may cause problems when combined with other medicines you take.



Chamomile is often used in the U.S. to help with anxiety and relaxation. In Europe, it's used to heal wounds and reduce inflammation and swelling. You can drink chamomile tea. Or you can use it as a compress. It's considered safe by the FDA. But it might make you feel more tired if you're taking other medicines. Be careful, as it could affect how some medicines work in your body.

Chamomile for the skin may be used to treat skin rash from radiation treatments. Chamomile in a capsule may be used to ease vomiting from chemotherapy.


(Leaf, stalk, root)

Echinacea is most often used to treat or prevent colds, flu, and infections, and for wound healing. Many studies have looked at how well it works to prevent or shorten a cold. The results have not been clear. Some studies do show some benefit of echinacea to help with upper respiratory infections.

Studies have shown that long-term use can affect the body's immune system. Because of this, only short-term use is advised. Check with your healthcare provider about any interactions with other medicines that you take. People allergic to plants in the daisy family may have an allergic reaction to echinacea. The daisy family includes ragweed, chrysanthemums, marigolds, and daisies.



Feverfew has been used to treat fevers. Some research has shown that feverfew can prevent migraines. It is also used to treat arthritis. If the leaves are chewed, side effects include mouth ulcers and digestive upset. Stopping feverfew suddenly may cause migraines to come back. Feverfew should not be used with NSAID medicine. These medicines may change how well feverfew works. Feverfew should not be used with warfarin or other medicines that thin the blood.


(Cloves, root)

Garlic is used in cooking. And it has proven health benefits. Garlic has been shown to fight germs, protect your heart, and reduce inflammation. It may help lower cholesterol and blood pressure. But the results are mixed. The FDA considers garlic safe. But it can increase your risk of bleeding. It should not be used with warfarin or other medicines that thin the blood. Don’t take large amounts before dental procedures or surgery. It may cause too much bleeding.



Ginger is most known for easing nausea and motion sickness. Research suggests it may help the nausea from pregnancy and chemotherapy. Ginger is in research for use in surgery and as an anticancer agent. It has strong anti-inflammatory effects. It is also a strong antioxidant. Side effects may include bloating, gas, heartburn, and nausea.



Ginkgo leaf extract is used for asthma, bronchitis, fatigue, and tinnitus. It is used to improve memory and to help prevent dementia. Some studies have shown it may work slightly. But how gingko works isn't fully known. Only extract from leaves should be used. Seeds have ginkgo toxin. This toxin can cause seizures. In large amounts, it can lead to death. Ginkgo may increase the risk of bleeding. Do not use it with NSAID medicines or other medicines that thin the blood. Do not use it with anticonvulsant medicines, or tricyclic antidepressants.



Ginseng is thought to boost energy, sex drive, and balance the body. Research is still unsure about its benefits. Side effects can include high blood pressure and fast heart rate. It's safe according to the FDA, but avoid it with certain medicines. Don’t take it with warfarin, heparin, or NSAID medicines. Don’t take it with estrogens, corticosteroids, or digoxin. People with diabetes should not use ginseng.


(Root, rhizome)

Goldenseal can help with diarrhea. It can help with eye and skin irritation. It can act as an antiseptic. It’s not proven to treat colds. Use it carefully. Too much can cause irritation of the skin, mouth, and stomach. Always follow a healthcare provider's instructions. Goldenseal can be poisonous in high doses.

Milk thistle


Milk thistle is used for liver problems and high cholesterol. It is also used to reduce the growth of cancer cells. Study results are not clear about its real benefits for liver disease.

Saint John's wort

(Flower, leaf)

Saint John's wort can help with mild to moderate depression. Results for severe depression are not clear. It can make your skin sensitive to light in high doses. It can interact with other medicines in dangerous ways. Make sure to talk to your healthcare provider before using this herb.

Saw palmetto


Saw palmetto is used to treat urine problems from an enlarged prostate. But recent studies have found it not to work for this. It can cause mild upset stomach or headaches.



Valerian is used to treat sleep problems and to reduce anxiety. Research shows it may work as a sleep aid, but the results are mixed. Talk with your healthcare provider before taking it.

Taking herbs safely

Before you use any herb as medicine, talk with your healthcare provider. Tell them all medicines and vitamins you take. They will need to make sure the herbal medicine is safe. Some herbs are unsafe to take with other medicines. Ask them how much is safe for you to take. Follow their instructions. Tell them if you have any side effects.

Online Medical Reviewer: Amy Finke RN BSN
Online Medical Reviewer: Bianca Garilli MD
Online Medical Reviewer: Heather M Trevino BSN RNC
Date Last Reviewed: 10/1/2023
© 2000-2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.