Perforate St. John's Wort

A genus of over 400 species of annuals, herbaceous perennials, and deciduous, semi-evergreen, and evergreen shrubs and trees, found mainly in temperate regions. This varied group provides many fine garden plants for most settings. Hypericum perforatum is a good subject for a wildflower meadow or woodland area. Hypericum may derive from the Greek hyper, "above", and eikon, "picture", since the flowers were placed above religious images to keep off evil at the northern Midsummer Day (June 24, St. John's Day). The alleged magical properties of H. perforatum were partly due to hypericin, the fluorescent red pigment that oozes like blood from the crushed flowers. As a medicinal herb, St. John's wort was traditionally used internally to treat nervous complaints and externally for healing, but fell into disuse int he 19th century. During the late 20th century, it underwent a revival following clinical trials that demonstrated its effectiveness in relieving mild to moderate depression and was described as "nature's Prozac". St. John's wort contains hypericin and hyperforin, which have anti-depressant effect; adhyperforin, which promotes wound healing; and also proanthocyanidins that benefit circulation. Standardized herbal preparations are graded according to their hypericin content, though other constituents may have an important role to play in the overall effect. St. John's wort is also a potent anti-viral and has potential in the development of drugs for treating human immuno-deficiency virus (HIV), viral hepatitis, and chronic fatigue syndrome. Synthetic hypericin is being developed as an antiretroviral agent for blood transfusions.

Named for St. John, the patron saint of nurses, this herb in medieval times was believed to br such a powerful healer that if people put a cutting of it under their pillow on St. John's Eve, St. John himself would appear in their dreams and ward off death for another year. The herb's scientific name, Hypericum, comes from the Greek word meaning "over an apparition", referring to the herb's purported ability to make evil spirits fly away with just one whiff of its pungent odor.

Upright, clump-forming perennial, woody at the base, with blunt, oblong-elliptic to linear leaves, 3cm (1¼in) long. Yellow, 5-petaled, gland-dotted flowers, 2cm (¾in) across, appear in large cymes in summer.

Common Name:
Perforate St. John's Wort
Other Names:
Amber, Common St. John's Wort, Goatweed, Grace of God, Hardhay, Hypericum, Johnswort, Klamath Weed, Pennyjohn, St. John's Wort, St. Johnswort, Tipton Weed, Witch's Herb.
Botanical Name:
Hypericum perforatum
Native Location:
Europe, W Asia
Well-drained to dry soil in sun or partial shade.
By seed sown in autumn; by division in autumn or spring. Self-seeds readily. Subject to statutory control as a weed in some countries, notably in Australia.
Plants are cut as flowering begins and used fresh or dried in creams, infusions, liquid extracts, medicated oils, and tinctures.
60cm-1m (2-3ft)
45-60cm (18-24in)
From ancient Greek and Roman times through the Middle Ages, herbalists treasured St. John's Wort as one of the best infection fighters and wound-healers in the plant kingdom. And they were right. We now know that St. Johnswort as potent bacterial- and virus-fighting properties. Then, during the Middle Ages, herbalists because using St. Johnswort in a new way—to treat those unfortunate souls afflicted with "hysteria", "madness", and "melancholy". Medieval herbalists believed such people were possessed by demons. And even though they used St. Johnswort as a kind of an herbal exorcist, they, too, were on the right track. There is indisputable evidence today that St. Johnswort is an effective treatment for mild depression—as effective as several conventional antidepressants and a good deal safer. That fact alone has made St. Johnswort the most widely used and most heatedly discussed of the current super herbs. It is the first herbal medicine to rival adn even replace more expensive pharmaceuticals, and the overall effect has been to push alternative and conventional medicine closer together.
Nevertheless, and like many of the great healing herbs, the June-blooming, yellow-blossomed St. Johnswort plant is as steeped in magic and myth as it is in medicinal value. Its genus name is from the Greek hyper, for "over" and eikon, for "apparition", and refers to the fact that the herb possessed protective powers over demons. The plant is named for the martyred John the Baptist, because it always blooms close to his saint's day, June 24, and because the plant's leaves ooze a red, bloodlike oil when rubbed. On St. John's Eve, June 23, the early Christians placed St. Johnswort under their pillows in the belief that St. John would appear to them in a dream and prevent them from dying during the next year. The beloved sixth-century saint, Columba, carried St. Johnswort with him as protection during his long years as a missionary in the wilds of Ireland and Scotland. It seems everyone, through the Middle Ages at least, carried a sprig of St. Johnswort as a talisman against evil and misfortune—stuffed into pockets and shoes, slipped into prayer books and hymnals. Now we've come full circle and can find St. Johnswort everywhere, again—in bottles and boxes,in supermarkets and drugstores—a millennium talisman against modern-day evils.
Parts Used:
Whole plant, flower, bud
A bitter-sweet, cooling herb that is astringent, calms the nerves, reduces inflammation, and promotes healing. Locally antiseptic and analgesic.
Medicinal Uses:
Internally for anxiety, mild to moderate depression, nervous tension, insomnia, enuresis (especially in children), menopausal disturbances, premenstrual syndrome, shingles, sciatica, and fribrositis. Not given to patients suffering from severe depression. Contraindicated with the following medications: oral contraceptives; warfarin; digoxin; anticonvulsants; theophylline; selective serotonin re-uptake inhibitors (SSRIs); triptans; cyclosporin; and with various anti-virals prescribed for HIV patients. Externally for bruises, injuries (especially deep or painful wounds involving nerve damage), sores, sciatica, neuralgia, cramps, sprains, and tennis elbow. Works well with Calendula officinalis (See, pot marigold) or Hamamelis virginiana (See, common witch hazel) for bruises. Used in homeopathy for pain and inflammation caused by nerve damage.
To treat depression, anxiety, worm infestation, asthma, gout, rheumatism, and burns. Germany's Commission E has approved the use of St. John's wort to treat anxiety, depressive moods, blunt injuries, inflammation of the skin, wounds, and burns.
St. Johnswort has antianxiety, antibacterial, antibiotic, antidepressant, anti-inflammatory, antispasmodic, antitumor, astringent, expectorant, pain-relieving, sedating, and wound-healing properties. Traditional indications for taking St. Johnswort internally include anxiety, chest congestion, colic, enuresis (bedwetting), headache, insomnia, intestinal problems, melancholy, menstrual cramping, and menstrual irregularities. It is applied externally, in ointment form, for burns, skin ailments, and wounds. Two primary chemical ingredients in St. Johnswort are responsible for most of the herb's therapeutic effects: hypericin and pseudohypericin.
Currently, St. Johnswort is also prescribed for fibromyalgia, mild clinical depression, seasonal affective disorder (SAD; a mild depression that occurs during late fall and winter when there is less sunlight), and sleep disorders.
In a number of research studies, St. Johnswort has also demonstrated significant antibacterial, antiviral, and antitumor activity against ear and throat infections, candida, the Epstein-Barr virus, hepatitis A and B, herpes, the HIV virus responsible for AIDS, brain, breast, and skin cancers, staph infections, and tuberculosis.
St. Johnswort is widely available as fresh and dried herb and in capsules, oils, tablets, teas, and tinctures. For mild depression, the herb is usually prescribed in capsule form—300 mg taken three times a day. For maximum effectiveness, all commercially prepared St. Johnswort products should be standardized to contain at least 0.3 percent hypericin, the plant's most valuable chemical constituent. Consult your medical practitioner about whether St. Johnswort is right for you.
Typical Dose:
A typical dose of St. John's wort in tablet/capsule form is approximately 300 mg Hypericum extract (standardized to 0.3 percent hypericin) taken three times daily.
Mild and transient side effects associated with St. Johnswort include stomach upset, and skin rashes. The most reported (and publicized) side effect of the herb is photosensitivity—and oversensitivity to the sun's skin-burning effects. This side effect, however, was first reported based on observations of cows who had grazed on huge quantities of the plant. When St. Johnswort is taken internally at therapeutic doses, photosensitivity is usually not a problem for most humans. Sunscreens and cover-ups will also help mitigate the sun's effects. People who work outdoors, however, or people who use St. Johnswort topically, should talk with their practitioner about taking extra precautions when using the herb.
If you suspect you are clinically depressed, do not self-treat with St. Johnswort. Depression is a serious illness. It should be evaluated and diagnosed by a qualified medical practitioner who will then oversee any treatment plan.
Special Note: As an antidepressant, St. Johnswort was first believed to belong to a class of drugs called monoamine oxidase inhibitors (MAOIs); Nardil and Parnate are well-known MAOIs. People taking St. Johnswort were told to avoid the same foods, beverages, and drugs that people on MAOIs had to avoid: red wine, sharp cheeses, pickled meats, soy, and decongestants, to name just a few items. Subsequent research, however, indicated that St. Johnswort was not an MAOI, but instead acted more like Prozac, a much safer antidepressant; and there were no special foods, beverages, or medications to be avoided. We suggest you err on the side of caution and talk to your practitioner about what you should avoid taking while you're on St. Johnswort.
Finally, if you are being treated with pharmaceuticals for cancer or AIDS, do not take St. Johnswort at the same time; talk with your medical practitioner first. Despite research indicating that St. Johnswort has anticancer and anti-HIV properties, several recent clinical studies suggest that the herb may interfere with the effects of certain cancer and AIDS drugs.
Possible Side Effects:
St. John's wort's side effects include dizziness, fatigue, restlessness, insomnia, constipation, and photosensitivity.
Drug Interactions:
Taking St. John's wort with these drugs may increase the risk of bleeding or bruising:
Antithrombin III, (Thrombate III)
Argatroban, (Argatroban)
Bivalirudin, (Angiomax)
Dalteparin, (Fragmin)
Danaparoid, (Orgaran)
Enoxaparin, (Lovenox)
Fondaparinux, (Arixtra)
Heparin, (Hepalean, Hep-Lock)
Lepirudin, (Refludan)
Tinzaparin, (Innohep)
Warfarin, (Coumadin, Jantoven)
Taking St. John's wort with these drugs may increase the risk of hypoglycemia (low blood sugar):
Acarbose, (Prandase, Precose)
Acetohexamide, (Acetohexamide)
Chlorpropamide, (Diabinese, Novo-Propamide)
Gliclazide, (Diamicron, Novo-Gliclazide)
Glimepiride, (Amaryl)
Glipizide, (Glucotrol)
Glipizide and Metformin, (Metaglip)
Gliquidone, (Beglynor, Glurenorm)
Glyburide, (DiaBeta, Micronase)
Glyburide and Metformin, (Glucovance)
Insulin, (Humulin, Novolin R)
Metformin, (Glucophage, Riomet)
Miglitol, (Glyset)
Nateglinide, (Starlix)
Pioglitazone, (Actos)
Repaglinide, (GlucoNorm, Prandin)
Rosiglitazone, (Avandia)
Rosiglitazone and Metformin, (Avandamet)
Tolazamide, (Tolinase)
Tolbutamide, (Apo-Tolbutamide, Tol-Tab)
Taking St. John's wort with these drugs may interfere with the effectiveness of the drug:
Acebutolol, (Novo-Acebutolol, Sectral)
Alprazolam, (Apo-Alpraz, Xanax)
Amlodipine, (Norvasc)
Amobarbital, (Amytal)
Amobarbital and Secobarbital, (Tuinal)
Amprenavir, (Agenerase)
Antithymocyte Globulin, Equine, (Atgam)
Antithymocyte Globulin, Rabbit, (Thymoglobulin)
Atenolol, (Apo-Atenol, Tenormin)
Atorvastin, (Lipitor)
Azathioprine, (Imuran)
Basiliximab, (Simulect)
Befunolol, (Bentos, Betaclar)
Bepridil, (Vascor)
Betaxolol, (Betoptic S, Kerlone)
Bisoprolol, (Monocor, Zebeta)
Bromazepam, (Apo-Bromazepam, Gen-Bromazepam)
Brotizolam, (Lendorm, Sintonal)
Butabarbital, (Butisol Sodium)
Butalbital, Acetaminophen, and Caffeine, (Esgic, fioricet)
Butalbital, Aspirin, and Caffeine, (Fiorinal)
Carteolol, (Cartrol, Ocupress)
Carvedilol, (Coreg)
Celiprolol, (Celiprolol)
Chlordiazepoxide, (Apo-Chlordiazepoxide, Librium)
Chlorzoxazone, (Strifon Forte)
Clobazam, (Alti-Clobazam, Frisium)
Clonazepam, (Klonopin, Rivotril)
Clorazepate, (Tranxene, T-Tab)
Clozapine, (Clozaril, Gen-Clozapine)
Cyclophosphamide, (Cytoxan, Neosar)
Cyclosporine, (Neoral, Sandimmune)
Cyproterone and Ethinyl Estradiol, (Diane-35)
Daclizumab, (Zenapax)
Delavirdine, (Rescriptor)
Diazepam, (Apo-Diazepam, valium)
Diltiazem, (Cardizem, Tiazac)
Efalizumab, (Raptiva)
Efavirenz, (Sustiva)
Esmolol, (Brevibloc)
Estazolam, (ProSom)
Estradiol, (Climara, Estrace)
Estradiol and Medroxyprogesterone, (Lunelle)
Estradiol and Norethindrone, (Activella, CombiPatch)
Estradiol and Testosterone, (Climacterone)
Estrogens (Conjugated A/Synthetic)(Cenestin)
Estrogens (Conjugated/Equine), (Congest, Premarin)
Estrogens (Conjugated/Equine) and Medroxyprogesterone, (Premphase, Prempro)
Estrogens (Esterified), (Estratab, Menest)
Estrogens (Esterified) ande Methyltestosterone, (Estratest, Estratest H.S.)
Estropipate, (Ogen, OrthoEst)
Ethinyl Estradiol, (Estinyl)
Ethinyl Estradiol and Desogestrel, (Cyclessa, Ortho-Cept)
Ethinyl Estradiol and Drospirenone, (Yasmin)
Ethinyl Estradiol and Ethynodiol Diacetate, (Demulen, Zovia)
Ethinyl Estradiol and Etonogestrel, (NuvaRing)
Ethinyl Estradiol and Levonorgestrel, (Alesse, Triphasil)
Ethinyl Estradiol and Norelgestromin, (Evra, Ortho Evra)
Ethinyl Estradiol and Norethindrone, (Brevicon, Ortho-Novum)
Ethinyl Estradiol and Norgestrel, (Cryselle, Ovral)
Etoposide, (Toposar, VePesid)
Felodipine, (Plendil, Renedil)
Flurazepam, (Apo-Flurazepam, Dalmane)
Fluvastatin, (Lescol)
Imatinib, (Gleevec)
Indinavir, (Crixivan)
Irinotican, (Camptosar)
Isradipine, (DynaCirc)
Labetalol, (Normodyne, Trandate)
Lacidipine, (Aponil, Caldine)
Lercanidipine, (Cardiovasc, Carmen)
Levobetaxolol, (Betaxon)
Levobunolol, (Betagan, Novo-Levobunolol)
Levonorgestrel, (Levonorgestrel)
Lopinavir and Ritonavir, (Kaletra)
Loprazolam, (Dormonoct, Havlane)
Lorazepam, (Ativan, Nu-Loraz)
Lovastatin, (Altocor, Mevacor)
Manidipine, (Calslot, Iperten)
Medroxyprogesterone, (Depo-Provera, Provera)
Mephobarbital, (Mebaral)
Mestranol and Norethindrone, (Necon 1/50, Ortho-Novum 1/50)
Methohexital, (Brevital, Brevital Sodium)
Methotrexate, (Rheumatrex, Trexall)
Metipranolol, (Optipranolol)
Metoprolol, (Betaloc, Lopressor)
Midazolam, (Apo-Midazolam, Versed)
Muromonab-CD2, (Orthoclone OKT 3)
Mycophenolate, (CellCept)
Nadolol, (Apo-Nadol, Corgard)
Nelfinavir, (Viracept)
Nevirapine, (Viramune)
Nicardipine, (Cardene)
Nifedipine, (Adalat CC, Procardia)
Nilvadipine, (Nilvadipine)
Nimodipine, (Nimotop)
Nisoldipine, (Sular)
Nitrendipine, (Nitrendipine)
Norgestrel, (Ovrette)
Oxazepam, (Novoxapam, Serax)
Oxprenolol, (Slow-Trasicor, Trasicor)
Paclitaxel, (Onzol, Taxol)
Pentobarbital, (Nembutal)
Phenobarbital, (Luminal Sodium, PMS-Phenobarbital)
Phenytoin, (Dilantin, Phenytek)
Pimecrolimus, (Elidel)
Pinaverium, (Dicetel)
Pindolol, (Apo-Pindol, Novo-Pindol)
Polyestradiol, (Polyestradiol)
Pravastatin, (Novo-Pravastatin, Pravachol)
Prazepam, (Prazepam)
Primidone, (Apo-Primidone, Mysoline)
Propranolol, (Inderal, InnoPran XL)
Quazepam, (Doral)
Reserpine, (Reserpine)
Ritonavir, (Norvir)
Rosuvastatin, (Crestor)
Saquinavir, (Fortovase, Invirase)
Secobarbital, (Seconal)
Simvastatin, (Apo-Simvastatin, Zocor)
Sirolimus, (Rapamune)
Sotalol, (Betapace, Sorine)
Tacrolimus, (Prograf, Protopic)
Tamoxifen, (Nolvadex, Tamofen)
Temazepam, (Novo-Temazepam, Restoril)
Tetrazepam, (Mobiforton, Musapam)
Thalidomide, (Thalomid)
Theophylline, (Elixophyllin, Uniphyl)
Thiopental, (Pentothal)
Timolol, (Betimol)
Triazolam, (Apo-Triazo, Halcion)
Verapamil, (Calan, Isoptin SR)
Taking St. John's wort with these drugs may interfere with the absorption of the drug:
Ferric Gluconate, (Ferrlecit)
Ferrous Fumarate, (Femiron, Feostat)
Ferrous Gluconate (Fergon, Novo-Ferrogluc)
Ferrous Sulfate, (Feratab, Fer-Iron)
Ferrous Sulfate and Ascorbic Acid, (FeroGrad 500, Vitelle Irospan)
Iron-Dextran Complex, (Dexferrum, INFeD)
Polysaccharide-Iron Complex, (Hytinic, Niferex)
Taking St. John's wort with these drugs may cause or increase serotonin syndrome (symptoms of which include agitation, rapid heart rate, flushing, heavy sweating, and possibly even death):
Amitriptyline, (Elavil, Levate)
Amitriptyline and Chlordiazepoxide, (Limbitrol)
Amitriptyline and Perphenazine, (Etrafor, Triavil)
Amoxapine, (Asendin)
Buspirone, (BuSpar, Nu-Buspirone)
Citalopram, (Celexa)
Clomipramine, (Anafranil, Novo-Clopramine)
Desipramine, (Alti-Desipramine, Norpramin)
Dextroamphetamine, (Dexedrine, Dextrostat)
Dextroamphetamine and Amphetamine, (Adderall, Adderall XR)
Doxepin, (Sinequan, Zonalon)
Fluoxetine, (Prozac, Sarafem)
Fluvoxamine, (Alti-Fluvoxamine, Luvox)
Imipramine, (Apo-Imipramine, Tofranil)
Iproniazid, (Marsilid)
Lofepramine, (Feprapax, Gamanil)
Melitracen, (Dixeran)
Methamphetamine, (Desoxyn)
Moclobemide, (Alti-Moclobemide, Nu-Moclobemide)
Nefazodone, (Serzone)
Nortriptyline, (Aventyl HCl, Pamelor)
Paroxetine, (Paxil)
Phenelzine, (Nardil)
Protriptyline, (Vivactil)
S-Citalopram, (Lexapro)
Selegiline, (Eldepryl)
Sertraline, (Apo-Sertraline, Zoloft)
Tranylcypromine, (Parnate)
Trazodone, (Desyrel, Novo-Trazodone)
Trimipramine, (Apo-Trimip, Surmontil)
Venlafaxine, (Effexor)
Taking St. John's wort with these drugs may increase the therapeutic and/or adverse effects of the drug:
Almotriptan, (Axert)
Eletriptan, (Relpax)
Frovatriptan, (Frova)
Taking St. John's wort with these drugs may increase skin sensitivity to sunlight:
Acemetacin, (Acemetacin Heumann, Acemetacin Sandoz)
Acetohexamide, (Acetohexamide)
Aminolevulinic Acid, (Levulan Kerastick)
Aspirin, (Bufferin, Ecotrin)
Azosemide, (Diat)
Benazepril, (Lotensin)
Bumetanide, (Bumex, Burinex)
Captopril, (Capoten, Novo-Captopril)
Celecoxib, (Celebrex)
Chlorothiazide, (Diuril)
Chlorpropamide, (Diabinese, Novo-Propramide)
Choline Magnesium Trisalicylate, (Trilisate)
Choline Salicylate, (Teejel)
Cilazapril, (Inhibace)
Delapril, (Adecut, Delakete)
Demeclocycline, (Declomycin)
Diclofenac, (Cataflam, Voltaren)
Diflunisal, (Apo-Diflunisal, Dolobid)
Dipyrone, (Analgina, Dinador)
Doxycycline, (Apo-Doxy, Vibramycin)
Enalapril, (Vasotec)
Erythromycin and Sulfisoxazole, (Eryzole, Pediazole)
Ethacrynic Acid, (Edecrin)
Etodolac, (Lodine, Utradol)
Etorcoxib, (Arcoxia)
Etozolin, (Elkapin)
Fenoprofen, (Nalfon)
Flurbiprofen, (Ansaid, Ocufen)
Fosinopril, (Monopril)
Furosemide, (Apo-Furosemide, Lasix)
Glimepiride, (Amaryl)
Glipizide, (Glucotrol)
Glyburide, (DiaBeta, Micronase)
Hydrochlorothiazide, (Apo-Hydro, Microzide)
Hydrochlorothiazide and Triamterene, (Dyazide, Maxzide)
Hydroflumethiazide, (Diucardin, Saluron)
Ibuprofen, (Advil, Motrin)
Imidapril, (Novarok, Tanatril)
Indomethacin, (Indocin, Novo-Methacin)
Ketoprofen, (Orudis, Rhodis)
Ketorolac, (Acular, Toradol)
Lisinopril, (Prinivil, Zestril)
Magnesium Salicylate, (Doan's, Mobidin)
Meclofenamate, (Meclomen)
Mefenamic Acid, (Ponstan, Ponstel)
Meloxicam, (MOBIC, Mobicox)
Methyclothiazide, (Aquatensen, Enduron)
Minocycline, (Dynacin, Minocin)
Moexipril, (Univasc)
Nabumetone, (Apo-Nabumetone, Relafen)
Naproxen, (Aleve, Naprosyn)
Niflumic Acid, (Niflam, Nifluril)
Nimesulide, (Areuma, Aulin)
Olmesartan and Hydrochlorothiazide, (Benicar HCT)
Oxaprozin, (Apo-Oxaprozin, Daypro)
Oxytetracycline, (Terramycin, Terramycin IM)
Perindopril Erbumine, (Aceon, Coversyl)
Piroxicam, (Feldene, Nu-Pirox)
Polythiazide, (Renese)
Quinapril, (Accupril)
Ramipril, (Altace)
Rofecoxib, (Vioxx)
Salsalate, (Amgesic, Salflex)
Spirapril, (Spirapril)
Sulfacetamide, (Bleph-10, Klaron)
Sulfadiazine, (Microsulfon)
Sulfamethoxazole and Trimethoprim, (Bactrim, Septra)
Sulfisoxazole, (Gantrisin)
Sulfur and Sulfacetamide, (Nocosyn, Rosanil)
Sulindac, (Clinoril, Nu-Sundac)
Tenoxicam, (Dolmen, Mobiflex)
Tetracycline, (Novo-Tetra, Sumycin)
Tiaprofenic Acid, (DomTiaprofenic, Surgam)
Tolazamide, (Tolinase)
Tolbutamide, (Apo-Tolbutamide, Tol-Tab)
Tolmetin, (Tolectin)
Torsemide, (Demadex)
Trandolapril, (Mavik)
Trichlormethiazide, (Metatensin, Naqua)
Valdecoxib, (Bextra)
Xipamide, (Diurexan, Lumitens)
Taking St. John's wort with these drugs may reduce blood levels of the drug:
Amiodarone, (Cordarone, Pacerone)
Digitalis, (Digitek, Lanoxin)
Methadone, (Dolophine, Methadose)
Taking St. John's wort with these drugs may be harmful:
Acitretin, (Soriatane)—may increase the risk of unplanned pregnancy and birth defects.
Carbamazepine, (Carbatrol, Tegretol)—may alter blood levels of the drug.
Loperamide, (Diarr-EZ, Imodium A-D)—may increase the risk of confusion, agitation, disorientation, and other symptoms of delirium.
Lab Test Alterations:
  • May increase levels of growth hormone (somatotropin, GH).
  • May decrease levels of serum prolactin.
  • May decrease levels of theophylline.
  • May decrease levels of serum iron.
  • May decrease levels of digitalis.
  • May decrease prothrombin time (PT) and plasma international normalized ratio (INR) in those who are also taking warfarin.
  • May increase thyroid-stimulating hormone (TSH) levels.
Disease Effects:
  • May trigger psychosis in those with Alzheimer's disease or schizophrenia.
  • May trigger mania or hypomania in those with bipolar disorder.
  • May trigger hypomania in those with major depression.
Food Interactions:
Because of the possible monoamine oxidase inhibiting (MAOI) action of St. John's wort, limit intake of foods high in tyramine, such as aged cheese, red wine, bananas, aged or cured meat, and yeast-containing products.
Supplement Interactions:
  • May decrease therapeutic effects of digitalis.
  • May increase positive and negative effects of herbs and supplements that have serotonergic properties, such as 5-hydroxytrytophan (5-HTP) and S-Adenosylmethionine (SAMe).
Harmful if eaten. Skin allergen in sunlight.
Encyclopedia of Herbs by Deni Brown Copyright © 1995, 2001 Dorling Kindersley Limited. pg 240
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.436-442
The Modern Herbal Primer by Nancy Burke Copyright©2000 Yankee Publishing, Inc. pp. 91-94