Herbal medicines or supplements are natural compounds from plants’ leaves, bark, roots, seeds, or flowers that people can use for medicinal purposes. They may offer therapeutic benefits when people use them as complementary medicine.

Herbal medicines contain active ingredients from natural plants. Their use dates back thousands of years, even before the invention of conventional medicine.

While many people prefer herbal medicines to some doctor-prescribed medications, others may use them in combination with prescription and nonprescription drugs.

This article outlines the different types of herbal medicines, their uses, safety precautions, and when to contact a doctor.

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Herbal medicines are natural botanical products, derived from plants, that people may use to treat and prevent diseases.

They are part of a category of treatments called complementary and alternative medicine. Currently, thousands of herbal medicine products are available over the counter in the United States.

Research from a 2018 focus-group study suggests that people may use herbal medicine because they are dissatisfied with conventional medicine. They may also use herbal medicines to:

  • treat mild and moderate conditions
  • start treatment before taking conventional medicine

Other common uses include:

However, a 2017 report published in the Journal of Patient Experience notes that factors associated with the use of herbal medicine include:

  • age older than 70
  • educational qualifications above high school
  • over-the-counter (OTC) medication use
  • use of a mail-order pharmacy

The World Health Organization estimates that 88% of countries use herbal medicine, noting that 40% of pharmaceutical drugs and landmark medications, including aspirin and artemisinin, originated from herbal medicine.

Learn about nine herbs for anxiety.

How a person takes herbal supplements depends on the form. They are available as tablets, capsules, teas, powders, extracts, and fresh or dried plants.

A person can take herbal supplements by:

  • swallowing them as pills, powders, or tinctures
  • applying them to the skin as gels and lotions
  • adding them to bathwater
  • drinking them as teas

Dosages for some herbal supplements may be challenging to get right. Many factors can affect the quality of herbal supplements, including the growing conditions, age, and preparation of the plant.

As a result, there is no standardized way to provide a correct dosage. If a person considers taking an herbal supplement, they should avoid self-prescribing and discuss it with a doctor first.

The doctor will ask questions about a person’s health condition and determine the best dosage for the desired pharmacological effect.

Because conventional medical doctors may not have received much education regarding herbal medicine, a person may instead want to consult a licensed naturopathic doctor, a licensed acupuncturist, or another qualified practitioner of herbal medicine.

A person should talk with a doctor before taking herbal medicine. The National Center for Complementary and Integrative Health warns that supplements can increase or decrease the effects and side effects of prescription and OTC drugs. Doctors can advise people about drug interactions they need to be careful of.

Safe use of herbal medicine also includes:

  • following label instructions carefully
  • taking only the recommended dosage
  • stopping taking an herbal supplement if it is ineffective

The United Kingdom’s National Health Service (NHS) notes that taking herbal medicine may not be suitable for a person if they are:

  • pregnant
  • breastfeeding
  • taking other prescription or OTC medications
  • over age 65
  • under age 18
  • having surgery

The NHS also notes that anyone taking herbal medicine should disclose it to their doctor before surgery. This is because some herbal medicines may interact with anesthesia drugs and affect blood pressure and blood clotting during and after surgery.

Some people use herbal supplements to treat specific symptoms, though there is not much formal research on these uses. The table below lists some herbal supplements and some conditions that they may benefit.

Using supplements can be unsafe for people who have certain health conditions or take medications. People who are breastfeeding or pregnant may want to avoid herbal supplements, as there is very little research on their effects.

Always consult a doctor before taking herbal supplements.

Herbal supplementWhat might it help?Precautions and potential side effects
aloe veraacne
• skin injuries, such as burns
digestive problems
• Topical use may cause burning, itching, and eczema.
• Oral aloe latex use may cause abdominal pain and cramping.
• Oral aloe leaf extract may increase acute hepatitis risk.
black cohoshmenopause symptomsmay cause stomach upset, cramping, headache, rash, vaginal spotting, and weight gain
• may lead to liver damage
echinaceacommon cold preventionmay cause nausea or stomach pain
garlichigh cholesterol• Oral supplements may increase the risk of bleeding, so they may be unsafe for people taking anticoagulants, such as warfarin, and those needing surgery.
• may interact with saquinavir, a drug used to treat HIV
ginkgo• age-related dementia
• anxiety
eye health
peripheral artery disease
premenstrual syndrome
may cause headache, stomach upset, dizziness, palpitations, constipation, skin reactions
• may increase risk of bleeding
ginger• mild stomach upset
nausea from pregnancy and chemotherapy
menstrual cramps
may cause abdominal discomfort, heartburn, diarrhea, and mouth and throat irritation, particularly in large doses
hawthorn• low blood pressure
• anxiety
• kidney issues
• heart disease
• digestion
may cause dizziness, nausea, and digestive symptoms
• may interact in a harmful way with heart medications
licorice root• digestive symptoms
atopic dermatitis
sore throat
unsuitable for people with high blood pressure, heart disease, or kidney disease
• may increase blood pressure and decrease potassium levels
• in large doses, may cause premature birth and infant health problems after birth
milk thistle• hepatitis
type 2 diabetes
may cause digestive issues
• may cause allergic reactions in people allergic to marigold, chamomile, or daisies
passionflower• sleep problems
• anxiety
may cause drowsiness, confusion, and uncoordinated movement
• unsuitable for use during pregnancy, as it may induce contractions
peppermint oil• irritable bowel syndrome
• abdominal pain
• indigestion
• tension headaches
cracked nipples
may cause nausea, heartburn, abdominal pain, and dry mouth
• may cause skin rashes and irritation if a person uses it topically
saw palmettobenign prostatic hyperplasiamay cause digestive symptoms or headache
soy• high cholesterol
• menopausal hot flashes
• high blood pressure
• bone health
may cause constipation or diarrhea
• may affect thyroid function in people with iron deficiency
turmeric• digestive issues
• bone health
may cause liver injury
• may cause mild dermatitis and stomach upset
valerian• menopause symptoms
• sleep problems
may cause headache, stomach upset, excitability, uneasiness, and heart issues

Learn about eight herbs and supplements for depression.

Does the FDA approve herbal medicines?

No, the FDA does not approve herbal medicines. This is because the FDA does not consider herbal medicines drugs. Instead, it considers them dietary supplements for complementary therapy.

As a result, herbal medicines are not subject to the same testing, labeling, and manufacturing standards as traditional prescription and OTC medications. However, the FDA regulates herbal medicines to ensure that they meet specific criteria and that they are not dangerous for human consumption.

Is herbal medicine safe?

Not necessarily. The NHS warns that “natural” does not mean safe if a person uses a product without a doctor’s prescription.

This is because some herbs can have adverse drug interactions with other medications. Some may also cause fatal side effects. A person should always check with a doctor before taking supplements if they have a health condition or are taking prescribed medication.

A person should discontinue using an herbal supplement and contact a doctor immediately if they experience any of the following symptoms:

They should also seek medical advice if they take an overdose of an herbal supplement.

If a person develops symptoms of a severe allergic reaction, they or other people around them should immediately call 911 or the local emergency number.

According to a 2017 review published in American Family Physician, 40–60% of U.S. adults use dietary supplements, including herbal medicines, and 25% report taking herbal supplements with prescription medication.

The authors note that many people who use herbal supplements do not disclose it to their doctors. This affects the clinical assessment and safety of specific herbal supplement-drug interactions.

To help healthcare professionals better evaluate herbal supplement interactions in the body, a person should:

  • disclose any herbal supplements they are using to their doctor
  • document their symptoms
  • stop using herbal supplements if symptoms do not improve
  • avoid herbal supplement overdose
  • report any worsening symptoms to their doctor

Herbal medicines or supplements are natural compounds made from plant parts. Manufacturers extract active ingredients from the plants’ leaves, bark, roots, seeds, or flowers.

Herbal supplements are available in many forms, such as pills, teas, extracts, and powders. People use them to treat chronic conditions, including anxiety, sleep problems, and low libido.

Herbal supplements are not FDA-approved, and some natural products may be unsafe. Herbal supplements can cause adverse drug reactions, so a person must consult a doctor before taking them if they are also taking prescription medication.