St. John’s Wort (Hypericum perforatum) is known for its antidepressant and calming effects, but it is not without risks. Although it is a popular natural remedy, its consumption can be dangerous in certain conditions or in combination with certain medications. Below, the major contraindications, cases where it is not indicated, and medical warnings supported by scientific research are presented in detail.
1. Not Recommended in Combination with Antidepressant Medications
St. John’s Wort contains hypericin and hyperforin, substances that influence serotonin levels in the brain. For this reason, taking it concurrently with synthetic antidepressants (such as SSRIs – selective serotonin reuptake inhibitors) can lead to serotonin syndrome, a serious condition that can cause confusion, agitation, fever, high blood pressure, and, in extreme cases, coma.
A study published in the Journal of Clinical Psychopharmacology (2001) showed that patients combining fluoxetine with St. John’s Wort extracts had an increased risk of serotonin syndrome, especially after 23 weeks of administration.
2. Interacts with Oral Contraceptives
One of the most discussed effects of St. John’s Wort tea is its reduction of the effectiveness of contraceptive pills. It stimulates the liver enzymes CYP3A4, leading to a faster metabolism of the hormones in contraceptives, thereby reducing their concentration in the blood.
According to a review published in the British Journal of Clinical Pharmacology (2003), regular use of St. John’s Wort led to ovulation in women taking combined contraceptives, even though they were previously under hormonal control.
3. Contraindicated in Pregnancy and Breastfeeding
Although it is a plant, its effects on hormones and the central nervous system can negatively influence pregnancy. There are not enough studies to confirm its safety for infants. Additionally, the active substances can pass into breast milk and affect the child.
The World Health Organization recommends avoiding St. John’s Wort during pregnancy, especially in the first trimester, due to the risk of uterine stimulation and hormonal effects on the fetus.
4. May Reduce the Effectiveness of Vital Medications
St. John’s Wort can accelerate the metabolism of some important medications, reducing their effectiveness. These include:
- Cyclosporine (immunosuppressant)
- Digoxin (for the heart)
- Warfarin (anticoagulant)
- Indinavir (antiviral medication for HIV)
- Theophylline (for asthma)
- Benzodiazepines (strong sedatives)
In a study published in The Lancet (2000), the plasma concentration of cyclosporine significantly decreased after St. John’s Wort administration, putting patients who had undergone organ transplants at risk.
5. Not Recommended for Individuals with Bipolar Disorder
St. John’s Wort can trigger manic episodes in individuals diagnosed with bipolar disorder. It stimulates brain activity and can exacerbate chemical imbalances in predisposed patients.
The American Psychiatric Association warns that patients with a history of mania should not use St. John’s Wort preparations without strict medical supervision.
6. May Increase Sensitivity to Sunlight (Photosensitivity)
Hypericin, the active component of the plant, increases skin sensitivity to UV rays. Frequent consumption of St. John’s Wort tea can lead to severe sunburns, irritations, or rashes even after short exposures.
A report from Photodermatology, Photoimmunology & Photomedicine documented cases of severe skin reactions in patients consuming St. John’s Wort and exposing themselves to sunlight or tanning beds.
7. Not Recommended Before Surgical Procedures
St. John’s Wort tea affects blood coagulation and interacts with anesthetics. It is recommended to discontinue consumption at least 2 weeks before scheduled surgeries.
The American Society of Anesthesiologists recommends discontinuing all natural supplements, including St. John’s Wort, before surgical procedures.
8. Contraindications for Individuals with Severe Liver Conditions
Since it stimulates liver enzymes, consuming St. John’s Wort can overburden an already affected liver. It may also interfere with hepatoprotective medications or treatments for hepatitis.
9. Not Recommended for Long-Term Use Without Breaks
Prolonged consumption (more than 4-6 weeks) without breaks can lead to the accumulation of hypericin in the body, with adverse effects such as sleep disturbances, anxiety, dizziness, and digestive problems.
10. Caution When Driving or Operating Machinery
St. John’s Wort tea can cause drowsiness, dizziness, or concentration disturbances in some individuals. In the first few days of use, it is advisable to avoid activities that require increased alertness.
Although St. John’s Wort is a plant with real therapeutic potential, it is not without risks. The tea should be consumed cautiously, only in short courses, and never in combination with medication treatments without medical advice. Before use, it is recommended to discuss with a phytotherapist or a pharmacist specialized in medicinal plants.
Sources:
- Journal of Clinical Psychopharmacology – Serotonin Syndrome and St. John’s Wort
- British Journal of Clinical Pharmacology – Interactions Between St. John’s Wort and Hormonal Contraceptives
- The Lancet – St. John’s Wort Induces the Cytochrome P450 Enzyme System
- World Health Organization – Safety of Medicinal Plants During Pregnancy
- American Psychiatric Association – Guidelines on Alternative Treatments for Depression
- American Society of Anesthesiologists – Herbal Supplements and Surgery
