Overview

St. John's wort is a plant native to Europe with yellow, star-shaped flowers. It's often used for depression but can cause serious interactions with some drugs.

St. John's wort is named after John the Baptist. The plant usually begins to flower around the 24th of June, the feast day of St. John the Baptist. It contains many chemicals that act on messengers in the brain that regulate mood.

People most commonly use St. John's wort for depression and mood disorders. There is some strong scientific evidence that it is effective for mild to moderate depression. St. John's wort is also used for symptoms of menopause and many other conditions, but there is no good scientific evidence to support most of these other uses.

St. John's wort is available in dietary supplements in the US. But France has banned its use in products because of drug interaction concerns. In other countries, St. John's wort is only available with a prescription.

Uses & Effectiveness ?

Likely Effective for

  • Depression. Taking specific St. John's wort extracts by mouth is effective for mild or moderate depression. Certain St. John's wort products might work as well as some prescription drugs and might cause fewer side effects.

Possibly Effective for

  • Symptoms of menopause. Taking St. John's wort by mouth seems to help reduce hot flashes and other symptoms of menopause.
  • Emotional distress caused by extreme focus on a physical symptom (somatic symptom disorder). Taking a specific St. John's wort product (LI 160, Lichtwer Pharma) seems to reduce symptoms of this condition.

Possibly Ineffective for

There is interest in using St. John's wort for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: St. John's wort is likely safe when used in doses up to 900 mg daily for up to 12 weeks. It can cause some side effects such as diarrhea, dizziness, trouble sleeping, restlessness, and skin tingling. St. John's wort interacts with many drugs. Let your healthcare provider know if you want to take St. John's wort.

St. John's wort is possibly unsafe when taken in large doses. It might cause severe skin reactions after sun exposure. Wear sun block outside, especially if you are light-skinned.

When applied to the skin: St. John's wort is possibly safe when it is applied to the skin once a week for four weeks. However, St. John's wort might cause severe skin reactions after sun exposure.

Special Precautions and Warnings

When taken by mouth: St. John's wort is likely safe when used in doses up to 900 mg daily for up to 12 weeks. It can cause some side effects such as diarrhea, dizziness, trouble sleeping, restlessness, and skin tingling. St. John's wort interacts with many drugs. Let your healthcare provider know if you want to take St. John's wort.

St. John's wort is possibly unsafe when taken in large doses. It might cause severe skin reactions after sun exposure. Wear sun block outside, especially if you are light-skinned.

When applied to the skin: St. John's wort is possibly safe when it is applied to the skin once a week for four weeks. However, St. John's wort might cause severe skin reactions after sun exposure.

Pregnancy: St. John's wort is possibly unsafe when taken by mouth during pregnancy. Taking St. John's wort while pregnant might cause birth defects in infants. Until more is known, don't use St. John's wort when pregnant.

Breast-feeding: St. John's wort is possibly unsafe when taken by mouth while breast-feeding. Infants can experience colic, drowsiness, and fussiness. Until more is known, don't use St. John's wort when breast-feeding.

Children: St. John's work is possibly safe when taken by mouth for up to 8 weeks in children 6-17 years-old.

Alzheimer disease: St. John's wort might make dementia worse in people with Alzheimer disease.

Bipolar disorder: St. John's wort can bring on mania in people with bipolar disorder, and can also speed up the cycling between depression and mania.

Depression: In people with major depression, St. John's wort might bring on mania, which can involve impulsive behavior.

Schizophrenia: St. John's wort might bring on psychosis in some people with schizophrenia.

Surgery: St. John's wort might affect serotonin levels in the brain, which could interfere with surgical procedures. Also, in people who have used St. John's wort, using anesthesia may lead to serious heart complications during surgery. Stop using St. John's wort at least two weeks before a scheduled surgery.

Interactions ?

    Major Interaction

    Do not take this combination

  • Alprazolam (Xanax) interacts with ST. JOHN'S WORT

    The body breaks down alprazolam to get rid of it. St. John's wort can increase how fast the body gets rid of alprazolam. This might decrease the effects of alprazolam.

  • Birth control pills (Contraceptive drugs) interacts with ST. JOHN'S WORT

    Some birth control pills contain estrogen. The body breaks down the estrogen in birth control pills to get rid of it. St. John's wort might increase the breakdown of estrogen. Taking St. John's wort along with birth control pills might decrease the effects of birth control pills. If you take birth control pills along with St. John's wort, use an additional form of birth control such as a condom.

  • Cyclosporine (Neoral, Sandimmune) interacts with ST. JOHN'S WORT

    The body breaks down cyclosporine to get rid of it. St. John's wort can increase how quickly the body breaks down cyclosporine. This might decrease how well cyclosporine works.

  • Digoxin (Lanoxin) interacts with ST. JOHN'S WORT

    St. John's wort might decrease how much digoxin the body absorbs. By decreasing how much digoxin the body absorbs, St. John's wort might decrease the effects of digoxin.

  • Imatinib (Gleevec) interacts with ST. JOHN'S WORT

    The body breaks down imatinib to get rid of it. St. John's wort might increase how quickly the body gets rid of imatinib. Taking St. John's wort along with imatinib might decrease the effects of imatinib.

  • Irinotecan (Camptosar) interacts with ST. JOHN'S WORT

    The body breaks down irinotecan to get rid of it. St. John's wort might increase how fast the body breaks down irinotecan. This might decrease the effects of irinotecan.

  • Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates) interacts with ST. JOHN'S WORT

    Some medications are changed and broken down by the liver. St. John's wort might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Medications for HIV/AIDS (Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs)) interacts with ST. JOHN'S WORT

    The body breaks down medications used for HIV/AIDS to get rid of them. St. John's wort can increase how quickly the body breaks down these medications. Taking St. John's wort might decrease how well some of these medications work.

  • Medications for HIV/AIDS (Protease Inhibitors) interacts with ST. JOHN'S WORT

    The body breaks down medications used for HIV/AIDS to get rid of them. Taking St. John's wort might increase how quickly the body breaks down these medications. Taking St. John's wort might decrease how well some of these medications work.

  • Medications moved by pumps in cells (P-Glycoprotein Substrates) interacts with ST. JOHN'S WORT

    Some medications are moved in and out of cells by pumps. St. John's wort might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.

  • Phenobarbital (Luminal) interacts with ST. JOHN'S WORT

    The body breaks down phenobarbital to get rid of it. St. John's wort might increase how quickly the body breaks down phenobarbital. This could decrease how well phenobarbital works and increase the risk of seizures.

  • Phenprocoumon (Marcoumar, others) interacts with ST. JOHN'S WORT

    The body breaks down phenprocoumon to get rid of it. St. John's wort increases how quickly the body breaks down phenprocoumon. This decreases the effects of phenprocoumon.

  • Phenytoin (Dilantin) interacts with ST. JOHN'S WORT

    The body breaks down phenytoin to get rid of it. St. John's wort might increase how quickly the body breaks down phenytoin. This might decrease the effects of phenytoin and increase the possibility of seizures.

  • Rivaroxaban (Xarelto) interacts with ST. JOHN'S WORT

    The body breaks down rivaroxaban to get rid of it. St. John's wort can increase how quickly the body breaks down rivaroxaban. This can decrease the effects of rivaroxaban.

  • Tacrolimus (Prograf) interacts with ST. JOHN'S WORT

    The body breaks down tacrolimus to get rid of it. St. John's wort can increase how quickly the body breaks down tacrolimus. This can decrease the effects of tacrolimus.

  • Warfarin (Coumadin) interacts with ST. JOHN'S WORT

    The body breaks down warfarin to get rid of it. St. John's wort might increase how quickly the body gets rid of warfarin. This might decrease the effects of warfarin and increase the risk of clotting. Be sure to have your blood checked regularly. The dose of your warfarin might need to be changed.

  • Mephenytoin (Mesantoin) interacts with ST. JOHN'S WORT

    Mephenytoin is changed and broken down by the body. St. John's wort increases how quickly this medication is broken down by the body. This might decrease the effects of mephenytoin.

  • Omeprazole (Prilosec) interacts with ST. JOHN'S WORT

    The body breaks down omeprazole to get rid of it. St. John's wort can increase how quickly the body breaks down omeprazole. This could decrease the effects of omeprazole.

  • Docetaxel (Taxotere) interacts with ST. JOHN'S WORT

    The body breaks down docetaxel to get rid of it. St. John's wort can increase how quickly the body breaks down docetaxel. This might decrease how well docetaxel works.

  • Ketamine (Ketalar) interacts with ST. JOHN'S WORT

    The body breaks down ketamine to get rid of it. St. John's wort might increase how fast the body breaks down ketamine. This might decrease the effects of ketamine.

  • Oxycodone (Oxycontin) interacts with ST. JOHN'S WORT

    The body breaks down oxycodone to get rid of it. St. John's wort might increase how fast the body breaks down oxycodone. This might decrease the effects of oxycodone.

    Moderate Interaction

    Be cautious with this combination

  • Aminolevulinic acid interacts with ST. JOHN'S WORT

    Aminolevulinic acid can make the skin sensitive to sunlight. St. John's wort might also increase sensitivity to sunlight. Taking St. John's wort along with aminolevulinic acid might increase the chances of sunburn, blistering or rashes on areas of skin exposed to sunlight. Be sure to wear sunblock and protective clothing when spending time in the sun.

  • Clopidogrel (Plavix) interacts with ST. JOHN'S WORT

    The body must convert clopidogrel to its active form. Taking St. John's wort increases how quickly the body converts clopidogrel to the active form. This might increase the effects and side effects of clopidogrel, such as bruising and bleeding.

  • Fexofenadine (Allegra) interacts with ST. JOHN'S WORT

    The body breaks down fexofenadine to get rid of it. St. John's wort might decrease how quickly the body gets rid of fexofenadine. This could increase the effects and side effects of fexofenadine.

  • Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates) interacts with ST. JOHN'S WORT

    Some medications are changed and broken down by the liver. St. John's wort might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates) interacts with ST. JOHN'S WORT

    Some medications are changed and broken down by the liver. St. John's wort might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Medications that increase sensitivity to sunlight (Photosensitizing drugs) interacts with ST. JOHN'S WORT

    Some medications might make the skin more sensitive to sunlight. St. John's wort might also make the skin more sensitive to sunlight. Using these products together might increase the risk of sunburn, blistering, or rashes when the skin is exposed to sunlight. Be sure to wear sunblock and protective clothing when spending time in the sun.

  • Procainamide interacts with ST. JOHN'S WORT

    St. John's wort extract might increase how much procainamide the body absorbs. This could increase the effects and side effects of procainamide. But it's not clear if this is a big concern.

  • Reserpine (Raudixin, others) interacts with ST. JOHN'S WORT

    Taking St. John's wort might decrease the effects of reserpine.

  • Tramadol (Ultram) interacts with ST. JOHN'S WORT

    The body breaks down tramadol to get rid of it. St. John's wort might increase how fast the body breaks down tramadol. This might decrease the effects of tramadol.

  • Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates) interacts with ST. JOHN'S WORT

    Some medications are changed and broken down by the liver. St. John's wort might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Gliclazide (Diamicron, others) interacts with ST. JOHN'S WORT

    The body breaks down gliclazide to get rid of it. St. John's wort might increase how quickly the body gets rid of gliclazide. This might decrease the effects of gliclazide.

  • Methadone (Dolophine) interacts with ST. JOHN'S WORT

    The body breaks down methadone to get rid of it. St. John's wort might increase how fast the body breaks down methadone. This might decrease the effects of methadone.

  • Zolpidem (Ambien) interacts with ST. JOHN'S WORT

    The body breaks down zolpidem to get rid of it. St. John's wort might increase how quickly the body breaks down zolpidem. Taking St. John's wort and taking zolpidem might decrease the effects of zolpidem.

  • Bupropion (Wellbutrin) interacts with ST. JOHN'S WORT

    The body breaks down bupropion to get rid of it. St. John's wort might increase how quickly the body breaks down bupropion. This might decrease the effects of bupropion.

  • Medications changed by the liver (Cytochrome P450 2B6 (CYP2B6) substrates) interacts with ST. JOHN'S WORT

    Some medications are changed and broken down by the liver. St. John's wort might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

  • Voriconazole (Vfend) interacts with ST. JOHN'S WORT

    The body breaks down voriconazole to get rid of it. St. John's wort might increase how quickly the body gets rid of voriconazole. Taking St. John's wort along with voriconazole might decrease its effects.

  • Fentanyl interacts with ST. JOHN'S WORT

    The body breaks down fentanyl to get rid of it. St. John's wort might increase how quickly the body gets rid of fentanyl. This might decrease the effects of fentanyl.

  • Finasteride (Proscar, Propecia) interacts with ST. JOHN'S WORT

    The body breaks down finasteride to get rid of it. St. John's wort might increase how quickly the body gets rid of finasteride. Taking St. John's wort along with finasteride might decrease its effects.

  • Ivabradine (Corlanor) interacts with ST. JOHN'S WORT

    The body breaks down ivabradine to get rid of it. St. John's wort might increase how fast the body breaks down ivabradine. This might decrease the effects of ivabradine.

  • Medications used for lowering cholesterol (Statins) interacts with ST. JOHN'S WORT

    The body breaks down some medications to get rid of them. St. John's wort can increase how fast the body gets rid of some medications used for lowering cholesterol. Taking St. John's wort along with these medications might decrease their effects.

  • Clozapine (Clozaril) interacts with ST. JOHN'S WORT

    The body breaks down clozapine to get rid of it. St. John's wort might increase how quickly the body breaks down clozapine. This might decrease how well clozapine works.

  • Indinavir (Crixivan) interacts with ST. JOHN'S WORT

    The body breaks down indinavir to get rid of it. St. John's wort might increase how quickly the body breaks down indinavir. This might decrease the effects of indinavir.

  • Serotonergic drugs interacts with ST. JOHN'S WORT

    St. John's wort might increase a brain chemical called serotonin. Some medications also have this effect. Taking St. John's wort along with these medications might increase serotonin too much. This might cause serious side effects including heart problems, seizures, and vomiting.

    Minor Interaction

    Be watchful with this combination

  • Methylphenidate (Concerta, others) interacts with ST. JOHN'S WORT

    Taking St. John's wort along with methylphenidate might decrease how well methylphenidate works. But it's not clear if this is a big concern.

  • Theophylline interacts with ST. JOHN'S WORT

    The body breaks down theophylline to get rid of it. St. John's wort might increase how quickly the body gets rid of theophylline. Taking St. John's wort along with theophylline might decrease its effects in some people.

  • Ambrisentan (Letairis) interacts with ST. JOHN'S WORT

    The body breaks down ambrisentan to get rid of it. St. John's wort might increase how quickly the body gets rid of ambrisentan. But this effect is probably not a big concern.

  • Boceprevir (Victrelis) interacts with ST. JOHN'S WORT

    St. John's wort contains a chemical called hypericin. Taking St. John's wort with boceprevir might increase the amount of hypericin in the body. This might increase the effects or side effects of St. John's wort.

Dosing

Talk to your healthcare provider before taking St. John's wort. It can interact with many different drugs.

St. John's wort extract is most commonly used by adults in doses of 600-900 mg by mouth daily, taken in 2-3 divided doses, for up to 12 weeks. St. John's wort is also available in ointments, creams, and gels. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.
View References

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
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