More evidence is needed to rate St. John’s wort for these uses.
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 LIKELY SAFE for most people when taken by mouth short-term. It can cause some side effects such as trouble sleeping, vivid dreams, restlessness, anxiety, irritability, stomach upset, fatigue, dry mouth, dizziness, headache, skin rash, diarrhea, and tingling. Take St John’s wort in the morning or lower the dose if it seems to be causing sleep problems.
- St. John’s wort seems to be safe when used in children under 12 years of age for up to 6 weeks.
- However, St. John’s wort is POSSIBLY UNSAFE when taken by mouth in large doses. It might cause severe reactions to sun exposure. Wear sun block outside, especially if you are light-skinned.
- Not enough is known about the safety of St. John’s wort when it is applied to the skin. To be safe, don’t use it topically.
- St. John’s wort interacts with many drugs (see the section below). Let your healthcare provider know if you want to take St. John’s wort. Your healthcare provider will want to review your medications to see if there could be any problems.
Special precautions & warnings:
- Pregnancy and breast-feeding: St. John’s wort is POSSIBLY UNSAFE when taken during pregnancy. There is some evidence that it can cause birth defects in unborn rats. No one yet knows whether it has the same effect in unborn humans. Nursing infants of mothers who take St. John’s wort can experience colic, drowsiness, and listlessness. Until more is known, don’t use St. John’s wort if you are pregnant or breast-feeding.
- Infertility: There are some concerns that St. John’s wort might interfere with conceiving a child. If you are trying to conceive, don’t use St. John’s wort, especially if you have known fertility problems.
- Attention deficit-hyperactivity disorder (ADHD): There is some concern that St. John’s wort might worsen symptoms of ADHD, especially in people taking the medication methylphenidate for ADHD. Until more is known, don’t use St. John’s wort if you are taking methylphenidate.
- Bipolar disorder: People with bipolar disorder cycle between depression and mania, a state marked by excessive physical activity and impulsive behavior. St. John’s wort can bring on mania in these individuals and can also speed up the cycling between depression and mania.
- Major depression: In people with major depression, St. John’s wort might bring on mania, a state marked by excessive physical activity and impulsive behavior.
- Schizophrenia: St. John’s wort might bring on psychosis in some people with schizophrenia.
- Alzheimer’s disease: There is concern that St. John’s wort might contribute to dementia in people with Alzheimer’s disease.
- Anesthesia and surgery: Use of anesthesia in people who have used St. John’s wort for six months may lead to serious heart complications during surgery. Stop using St. John’s wort at least two weeks before a scheduled surgery.
Are there interactions with medications?
Major
Do not take this combination.
Methylphenidate (Concerta, Daytrana, Metadate, Ritalin)
- Taking St. John's wort along with methylphenidate might decrease how well methylphenidate works for controlling symptoms of attention deficit-hyperactivity disorder (ADHD).
Theophylline
- 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.
Are there interactions with herbs and supplements?
There are no known interactions with herbs and supplements.
Are there interactions with foods?
There are no known interactions with foods.
What dose is used?
The following doses have been studied in scientific research:
BY MOUTH:
For mild to moderate depression:
- When using St. John’s wort extract standardized to 0.3% hypericin content: 300 mg three times daily.
- When using a St. John’s wort extract standardized to 0.2% hypericin: 250 mg twice daily.
- When using a St. John’s wort extract standardized to 5% hyperforin: 300 mg three times daily.
- For children under 12 years of age with depression: St. John’s wort extract standardized to 0.3% hypericin 300 mg daily.
- For premenstrual syndrome (PMS): St. John’s wort extract standardized to 0.3% hypericin dosed at 300 mg once daily.
- For body symptoms associated with depression: 300 mg three times daily of the standardized hypericin extract has been used.
- For somatization disorder: a specific extract (LI 160, Lichtwer Pharma) 600 mg/day has been used.
Do not suddenly stop taking St. John’s wort. This might cause unpleasant side effects. If you decide to stop taking St. John’s wort, reduce the dose slowly over time.
Other names
Amber, Amber Touch-and-Heal, 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, Tipton Weed.