St. John's Wort

• What other names is St. John's Wort known by?
• What is St. John's Wort?
• Is St. John's Wort effective?
• How does St. John's Wort work?
• Are there safety concerns?
• Are there any interactions with medications?

What other names is St. John's Wort known by?

Amber, Amber Touch-and-Heal, Demon Chaser, Fuga Daemonum, Goatweed, Hardhay, Hypereikon, Hyperici Herba, Hypericum perforatum, Klamath Weed, Millepertuis, Rosin Rose, Saynt Johannes Wort, SJW, Tipton Weed.

What is St. John's Wort?

St. John's wort is an herb. Its flowers and leaves are used to make medicine.

Is St. John's Wort effective?

St. John’s wort can help for treatment of mild to moderate depression. It’s about as effective as some prescription drugs. However, it might not be as effective for severe depression.

There is also some scientific evidence that St. John’s wort might be effective for treating anxiety.

Oily preparations of St. John’s wort seem to help stomach upset when taken by mouth. When applied to the skin, these oily preparations seem to help first degree burns, cuts and bruises, and muscle pain.

There is also some evidence that St. John’s wort is not effective for treating HIV infection. Don’t use St. John’s wort for this condition.

There isn’t enough information to know if St. John’s wort is effective for the other conditions people use it for, including: migraine headache, nerve pain, sciatica, excitability, muscle pain, cancer, obsessive compulsive behavior, premenstrual syndrome (PMS), and many others.

Likely Effective for...

• Mild to moderate depression. St. John's wort might not be as effective for more severe cases of depression.

Possibly Effective for...

• Menopausal symptoms. Some research shows that a combination of St. John's wort plus black cohosh can help improve menopausal symptoms.
• Somatization disorder.

Possibly Ineffective for...

• Hepatitis C virus (HCV) infection.
• HIV/AIDS.
• Pain conditions related to diabetes (polyneuropathy).

Insufficient Evidence to Rate Effectiveness for...

• Stomach upset, bruises, skin conditions, migraine headache, nerve pain, sciatica, excitability, fibromyalgia, chronic fatigue syndrome (CFS), muscle pain, cancer, obsessive compulsive disorder (OCD), seasonal affective disorder (SAD), premenstrual syndrome (PMS), attention deficit-hyperactivity disorder (ADHD), smoking cessation, and other conditions.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

How does St. John's Wort work?

For a long time, investigators thought a chemical in St. John's wort called hypericin was responsible for its effects against depression. More recent information suggests another chemical, hyperforin, may play a larger role in depression. Hypericin and hyperforin act on chemical messengers in the nervous system that regulate mood.

Are there safety concerns?

St. John's wort is safe for most people when taken by mouth short-term. It can cause some side effects such as insomnia, vivid dreams, restlessness, anxiety, irritability, stomach upset, fatigue, dry mouth, dizziness, headache, skin rash, diarrhea, and tingling.

St. John's wort can cause skin to become extra sensitive to the sun. Wear sunblock outside, especially if you are light-skinned.

Do not use St. John's wort if:

• You are pregnant or breast-feeding.
• You are trying to get pregnant or father a child.
• You have attention deficit-hyperactivity disorder (ADHD).
• You have bipolar disorder.
• You have schizophrenia.
• You have Alzheimer's disease.
• You have major depression.
• You are scheduled for surgery in the next two weeks.

Are there any interactions with medications?

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Alprazolam (Xanax)
Interaction Rating: Major Do not take this combination.

Alprazolam (Xanax) is commonly used for anxiety. The body breaks down alprazolam (Xanax) to get rid of it. St. John's wort can increase how fast the body gets rid of alprazolam (Xanax). Taking St. John's wort along with alprazolam (Xanax) might decrease the effectiveness of alprazolam (Xanax).

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Aminolevulinic acid
Interaction Rating: Major Do not take this combination.

Aminolevulinic acid can make your skin sensitive to the sunlight. St. John's wort might also increase your 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.

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Amitriptyline (Elavil)
Interaction Rating: Major Do not take this combination.

The body breaks down amitriptyline (Elavil) to get rid of it. St. John's wort can increase how quickly the body gets rid of some medications. St. John's wort might decrease the effectiveness of amitriptyline (Elavil) by increasing how quickly the body breaks down amitriptyline (Elavil).

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Birth control pills (Contraceptive drugs)
Interaction Rating: Major Do not take this combination.

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 break down of estrogen. Taking St. John's wort along with birth control pills might decrease the effectiveness 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.

Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

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Cyclosporine (Neoral, Sandimmune)
Interaction Rating: Major Do not take this combination.

The body breaks down cyclosporine (Neoral, Sandimmune) to get rid of it. St. John's wort might increase how quickly the body breaks down cyclosporine (Neoral, Sandimmune). By increasing the breakdown of cyclosporine (Neoral, Sandimmune) St. John's wort might decrease the effectiveness of cyclosporine (Neoral, Sandimmune). Do not take St. John's wort if you are taking cyclosporine (Neoral, Sandimmune).

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Digoxin (Lanoxin)
Interaction Rating: Major Do not take this combination.

Digoxin (Lanoxin) helps the heart beat more strongly. St. John's wort might decrease how much digoxin (Lanoxin) the body absorbs. By decreasing how much digoxin (Lanoxin) the body absorbs St. John's wort might decrease the effects of digoxin (Lanoxin).

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Fenfluramine (Pondimin)
Interaction Rating: Major Do not take this combination.

Fenfluramine (Pondimin) increases a chemical in the brain. This chemical is called serotonin. St. John's wort also increases serotonin. Taking fenfluramine with St. John's wort might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, nausea, headache, and anxiety.

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Imatinib (Gleevec)
Interaction Rating: Major Do not take this combination.

The body breaks down imatinib (Gleevec) to get rid of it. St. John's wort might increase how quickly the body gets rid of imatinib (Gleevec). Taking St. John's wort along with imatinib (Gleevec) might decrease the effectiveness of imatinib (Gleevec). Do not take St. John's wort if you are taking imatinib (Gleevec).

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Irinotecan (Camptosar)
Interaction Rating: Major Do not take this combination.

Irinotecan (Camptosar) is used to treat cancer. The body breaks down irinotecan (Camptosar) to get rid of it. St. John's wort might increase how fast the body breaks down irinotecan (Camptosar) and decrease the effectiveness of irinotecan (Camptosar).

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Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Interaction Rating: Major Do not take this combination.

Some medications are changed and broken down by the liver. St. John's wort might increase how quickly the liver breaks down some medications. Taking St. John's wort along with some medications that are broken down by the liver can decrease the effectiveness of some medications. Before taking St. John's wort talk to your healthcare provider if you are taking any medications that are changed by the liver.

Some medications changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and many others.

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Medications for depression (Antidepressant drugs)
Interaction Rating: Major Do not take this combination.

St. John's wort increases a brain chemical called serotonin. Some medications for depression also increase the brain chemical serotonin. Taking St. John's wort along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take St. John's wort if you are taking medications for depression.

Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others.

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Medications for HIV/AIDS (Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs))
Interaction Rating: Major Do not take this combination.

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

Some of these medications used for HIV/AIDS include nevirapine (Viramune), delavirdine (Rescriptor), and efavirenz (Sustiva).

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Medications for HIV/AIDS (Protease Inhibitors)
Interaction Rating: Major Do not take this combination.

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. This could decrease the effectiveness of some medications used for HIV/AIDS.

Some of these medications used for HIV/AIDS include amprenavir (Agenerase), nelfinavir (Viracept), ritonavir (Norvir), and saquinavir (Fortovase, Invirase).

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Medications for pain (Narcotic drugs)
Interaction Rating: Major Do not take this combination.

The body breaks down some medications for pain to get rid of them. St. John's wort might decrease how fast the body gets rid of some medications for pain. By decreasing how fast the body gets rid of some medications for pain, St. John's wort might increase the effects and side effects of some medications for pain.

Some medications for pain include meperidine (Demerol), hydrocodone, morphine, oxycodone (OxyContin), and many others.

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Medications moved by pumps in cells (P-Glycoprotein Substrates)
Interaction Rating: Major Do not take this combination.

Some medications are moved by pumps in cells. St. John's wort can make these pumps more active and decrease how much of some medications get absorbed by the body. This might decrease the effectiveness of some medications.

Some medications that are moved by these pumps include etoposide, paclitaxel, vinblastine, vincristine, vindesine, ketoconazole, itraconazole, amprenavir, indinavir, nelfinavir, saquinavir, cimetidine, ranitidine, diltiazem, verapamil, corticosteroids, erythromycin, cisapride (Propulsid), fexofenadine (Allegra), cyclosporine, loperamide (Imodium), quinidine, and others.

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Medications that increase sensitivity to sunlight (Photosensitizing drugs)
Interaction Rating: Major Do not take this combination.

Some medications can increase sensitivity to sunlight. St. John's wort might also increase your sensitivity to sunlight. Taking St. John's wort along with medications that increase sensitivity to sunlight could 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.

Some drugs that cause photosensitivity include amitriptyline (Elavil), Ciprofloxacin (Cipro), norfloxacin (Noroxin), lomefloxacin (Maxaquin), ofloxacin (Floxin), levofloxacin (Levaquin), sparfloxacin (Zagam), gatifloxacin (Tequin), moxifloxacin (Avelox), trimethoprim/sulfamethoxazole (Septra), tetracycline, methoxsalen (8-methoxypsoralen, 8-MOP, Oxsoralen), and Trioxsalen (Trisoralen).

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Meperidine (Demerol)
Interaction Rating: Major Do not take this combination.

St. John's wort increases a chemical in the brain called serotonin. Meperidine (Demerol) can also increase serotonin in the brain. Taking St. John's wort along with meperidine (Demerol) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.

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Nefazodone (Serzone)
Interaction Rating: Major Do not take this combination.

Nefazodone (Serzone) can increase a chemical in the brain. This chemical is called serotonin. St. John's wort can also increase serotonin. Taking St. John's wort with nefazodone (Serzone) might cause there to be too much serotonin. This could lead to serious side effects including heart problems, shivering, and restlessness.

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Nortriptyline (Pamelor)
Interaction Rating: Major Do not take this combination.

The body breaks down nortriptyline (Pamelor) to get rid of it. St. John's wort can increase how quickly the body breaks down nortriptyline (Pamelor). This could decrease the effectiveness of nortriptyline (Pamelor).

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Paroxetine (Paxil)
Interaction Rating: Major Do not take this combination.

Paroxetine (Paxil) increases a chemical in the brain. This chemical is called serotonin. St. John's wort also increases serotonin. Taking paroxetine (Paxil) and St. John's wort together might cause there to be too much serotonin. This could lead to serious side effects including heart problems, shivering, and weakness.

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Pentazocine (Talwin)
Interaction Rating: Major Do not take this combination.

St. John's wort increases a brain chemical called serotonin. Pentazocine (Talwin) also increases serotonin. Taking St. John's wort along with pentazocine (Talwin) might increase serotonin too much. This could cause serious side effects including heart problems, shivering, and anxiety. Do not take St. John's wort if you are taking pentazocine (Talwin).

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Phenobarbital (Luminal)
Interaction Rating: Major Do not take this combination.

The body breaks down phenobarbital (Luminal) 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.

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Phenprocoumon
Interaction Rating: Major Do not take this combination.

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 effectiveness of phenprocoumon.

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Phenytoin (Dilantin)
Interaction Rating: Major Do not take this combination.

The body breaks down phenytoin (Dilantin) to get rid of it. St. John's wort might increase how quickly the body breaks down phenytoin. Taking St. John's wort and taking phenytoin (Dilantin) might decrease the effectiveness of phenytoin (Dilantin) and increase the possibility of seizures.

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Reserpine
Interaction Rating: Major Do not take this combination.

St. John's wort can decrease the effects of reserpine.

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Sedative medications (Barbiturates)
Interaction Rating: Major Do not take this combination.

Medications that cause sleepiness and drowsiness are called sedatives. St. John's wort might decrease the effectiveness of sedative medications. It is not clear why this interaction occurs.

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Sertraline (Zoloft)
Interaction Rating: Major Do not take this combination.

Sertraline (Zoloft) can increase a chemical in the brain. This chemical is called serotonin. St. John's wort also increases serotonin. This can cause there to be too much serotonin in the brain. This could lead to serious side effects including heart problems, shivering, and irritability.

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Tacrolimus (Prograf, Protopic)
Interaction Rating: Major Do not take this combination.

The body breaks down tacrolimus (Prograf, Protopic) to get rid of it. St. John's wort can increase how quickly the body breaks down tacrolimus (Prograf, Protopic). This can cause tacrolimus (Prograf, Protopic) to be less effective.

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Tramadol (Ultram)
Interaction Rating: Major Do not take this combination.

Tramadol (Ultram) can affect a chemical in the brain called serotonin. St. John's wort can also affect serotonin. Taking St. John's wort along with tramadol (Ultram) might cause too much serotonin in the brain and side effects including confusion, shivering, stiff muscles, and other side effects.

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Warfarin (Coumadin)
Interaction Rating: Major Do not take this combination.

Warfarin (Coumadin) is used to slow blood clotting. The body breaks down warfarin (Coumadin) to get rid of it. St. John's wort might increase the breakdown and decrease the effectiveness of warfarin (Coumadin). Decreasing the effectiveness of warfarin (Coumadin) might increase the risk of clotting. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

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Clopidogrel (Plavix)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down clopidogrel (Plavix) to a chemical that decreases blood clotting in the body. Taking St. John's wort along with clopidogrel (Plavix) might increase how well the body breaks down clopidogrel (Plavix) and decrease blood clotting too much.

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Dextromethorphan (Robitussin DM, and others)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

St. John's wort can affect a brain chemical called serotonin. Dextromethorphan (Robitussin DM, others) can also affect serotonin. Taking St. John's wort along with dextromethorphan (Robitussin DM, others) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety. Do not take St. John's wort if you are taking dextromethorphan (Robitussin DM, and others).

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Fexofenadine (Allegra)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down fexofenadine (Allegra) to get rid of it. St. John's wort might decrease how quickly the body gets rid of fexofenadine. This could cause fexofenadine (Allegra) to stay in the body too long. This could lead to increased effects and side effects of fexofenadine (Allegra).

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Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications are changed and broken down by the liver. St. John's wort might increase how quickly the liver breaks down some medications. Taking St. John's wort along with some medications that are changed by the liver can decrease the effectiveness of some medications. Before taking St. John's wort talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), zileuton (Zyflo), zolmitriptan (Zomig), and others.

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Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications are changed and broken down by the liver. St. John's wort might increase how quickly the liver breaks down some medications. Taking St. John's wort along with some medications that are broken down by the liver can decrease the effectiveness of your medication. Before taking St. John's wort talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include amitriptyline (Elavil), diazepam (Valium), zileuton (Zyflo), celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), and others.

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Medications for depression (MAOIs)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

St. John's wort increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking St. John's wort with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.

Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

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Medications for migraine headaches ("Triptans")
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications for migraine headaches can affect a chemical in the brain called serotonin. St. John's wort can also affect serotonin. Taking St. John's wort along with some medications for migraine headache might cause too much serotonin in the brain and serious side effects including confusion, shivering, stiff muscles, and other side effects.

Some medications for migraine headache include frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Imitrex), and zolmitriptan (Zomig).

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Procainamide
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

St. John's wort extract might increase how much procainamide the body absorbs. This could increase the effects and side effects of procainamide. But the significance of this potential interaction is not known.

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Simvastatin (Zocor)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down simvastatin (Zocor) to get rid of it. St. John's wort increases how quickly the body breaks down simvastatin (Zocor). This can cause simvastatin (Zocor) to be less effective.

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Methylphenidate (Concerta, Daytrana, Metadate, Ritalin)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Taking St. John's wort along with methylphenidate might decrease how well methylphenidate works for controlling symptoms of attention deficit-hyperactivity disorder (ADHD).

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Theophylline
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

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 the effectiveness of theophylline. But it is not clear if this interaction is a big concern.