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St. John's wort

Generic Name: St. John's wort (SAINT JOHN'S WORT)
Brand Name: St. John's Wort

Medically reviewed on Feb 16, 2018

What is St. John's wort?

St. John's wort is an herb also known as Amber, Barbe de Saint-Jean, Chasse-diable, Demon Chaser, Fuga Daemonum, Goatweed, Hardhay, Herbe à la Brûlure, Herbe à Mille Trous, Herbe Aux Fées, Herbe Aux Mille Vertus, Herbe Aux Piqûres, Herbe de Saint Éloi, Herbe de la Saint-Jean, Herbe du Charpentier, Herbe Percée, Hierba de San Juan, Hypereikon, Hyperici Herba, Hypericum perforatum, Klamath Weed, Millepertuis, Millepertuis Perforé, Rosin Rose, Saynt Johannes Wort, SJW, or Tipton Weed.

St. John's wort has been used in alternative medicine as a likely effective aid in treating mild to moderate depression and related symptoms such as anxiety or insomnia.

St. John's wort has been used in alternative medicine as a possibly effective aid in treating somatization disorder (physical illness or symptoms without a known cause), or hot flashes caused by menopause. Topical forms of St. John's wort have been possibly effective in healing skin wounds, or treating skin irritation caused by psoriasis.

St. John's wort has also been used to treat attention deficit hyperactivity disorder (ADHD), social anxiety, hepatitis C, irritable bowel syndrome, diabetic nerve pain, or burning mouth syndrome. However, research has shown that St. John's wort may not be effective in treating these conditions.

Other uses not proven with research have included anxiety disorder, obsessive compulsive disorder (OCD), premenstrual syndrome (PMS), seasonal affective disorder (SAD), genital herpes or cold sores, sciatic nerve pain, fibromyalgia, chronic fatigue syndrome, migraine headaches, weight loss, or smoking cessation.

It is not certain whether St. John's wort is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. St. John's wort should not be used in place of medication prescribed for you by your doctor.

St. John's wort is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

St. John's wort may also be used for purposes not listed in this product guide.

Important Information

Many drugs can interact with St. John's wort, and serious drug interactions can occur when certain medicines are used at the same time. Do not take St. John's wort without medical advice if you regularly use other medicines.

Avoid exposure to sunlight while taking St. John's wort. This product can make you sunburn more easily.

Before taking this medicine

Many drugs can interact with St. John's wort, and serious drug interactions can occur when certain medicines are used at the same time. Do not take St. John's wort without medical advice if you regularly use other medicines, especially;

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

St. John's wort may harm an unborn baby. Do not use this product without medical advice if you are pregnant.

St. John's wort can make birth control pills less effective. Ask your doctor about using non hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

St. John's wort may affect fertility (your ability to have children). You should not use this product if you are trying to get pregnant.

St. John's wort may pass into breast milk and may cause unwanted effects in a nursing baby. Do not use this product without medical advice if you are breast-feeding a baby.

St. John's wort should not be given to a child younger than 6 years old. St. John's wort is thought to be possibly safe for children ages 6 to 17 years old when taken for up to 8 weeks.

How should I take St. John's wort?

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use St. John's wort, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Do not use different forms (tablets, capsules, liquid, tincture, teas, etc) of St. John's wort at the same time without medical advice. Using different formulations together increases the risk of an overdose.

Take St. John's wort in the morning if this product causes you to have trouble sleeping.

Do not take topical (for the skin) St. John's wort by mouth. Topical forms of this product are for use only on the skin.

St. John's wort may increase your risk of serious heart complications or other problems during surgery. If you need surgery, stop taking St. John's wort at least 2 weeks ahead of time.

Call your doctor if the condition you are treating with St. John's wort does not improve, or if it gets worse while using this product.

Store at room temperature away from moisture, heat, and light. Exposure to light can make St. John's wort inactive.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra St. John's wort to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking St. John's wort?

Do not take St. John's wort together with other herbal/health supplements without medical advice.

Avoid exposure to sunlight or tanning beds. St. John's wort can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Avoid taking St. John's wort with other medicines that can make you more sensitive to sunlight, especially antibiotic medicine or a sulfa drug.

St. John's wort side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Although not all side effects are known, St. John's wort is thought to be likely safe when taken by an adult for up to 12 weeks, or by a child age 6-17 for up to 8 weeks. St. John's wort may be unsafe when taken in large doses.

Stop using St. John's wort and call your healthcare provider at once if you have:

  • severe skin rash or irritation;

  • severe sunburn (redness, burning, blistering) after being outdoors; or

  • (if you are also taking an antidepressant or narcotic pain medicine) -- agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting.

Common side effects may include:

  • sleep problems (insomnia), strange dreams;

  • feeling anxious, irritable, or restless;

  • dry mouth, upset stomach, diarrhea;

  • skin rash, tingly feeling;

  • headache, dizziness; or

  • tired feeling.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect St. John's wort?

Many drugs can interact with St. John's wort, and some drugs should not be used together. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using during your treatment with St. John's wort. Give a list of all your medicines to any healthcare provider who treats you.

Further information

  • Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.