Botanical name: Passiflora incarnata
© Steven Foster
Parts used and where grown
Passion flower is a climbing vine renowned for its beautiful white flowers with purple,
blue, or pink calyx crown blooms. The plant is native to North, Central, and South America.
While primarily tropical, some of its 400 species can grow in colder climates. The mystery of
such a beautiful blossom emerging from an unassuming bud has been compared to the Passion of
Christ. This inspired the plant’s name, which dates back to the 17th century. The
leaves, stems, and flowers are used for medicinal purposes.
Passion flower has been
used in connection with the following conditions (refer to the
individual health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
The historical use of passion flower is not dissimilar to its current use as a mild
sedative. Medicinal use of the herb did not begin until the late 19th century in the United
States. Passion flower was used to treat nervous restlessness and gastrointestinal spasms. In
short, the effects of passion flower were believed to be primarily on the nervous system,
particularly for anxiety due to mental worry
and overwork.1
The effectiveness of passion flower as a treatment for anxiety has been confirmed in a
double-blind study. In that study, 45 drops per day of an extract of passion flower taken for
four weeks was as effective as 30 mg per day of
oxazepam (Serax®), a medication used for anxiety.2
Active constituents
For many years, plant researchers believed that a group of harman alkaloids were the active
constituents in passion flower. Recent studies, however, have pointed to the flavonoids in passion flower as the primary
constituents responsible for its relaxing and anti-anxiety effects.3 European
herbal pharmacopoeias typically recommend passion flower products containing no less than 0.8%
total flavonoids. The European literature involving passion flower recommends it primarily for
the treatment of mild to moderate anxiety. In
this context, it is often combined with
valerian, lemon balm, and other herbs with
sedative properties.
How much is usually taken?
The recommended intake of the dried herb is 4–8 grams per day.4 To make a
tea, 0.5 to 2.5 grams of the herb can be steeped with boiling water for ten to fifteen minutes
and drunk two to three times per day. Alternatively, 5–10 ml of passion flower tincture
can be taken three to four times per day.
Are there any side effects or interactions?
Used in the amounts listed above, passion flower is generally safe and has not been found
to adversely interact with other sedative drugs. Some practitioners suggest not using passion
flower with MAO-inhibiting antidepressant
drugs because of concerns that they may interact with the harman alkaloids in passion
flower.5 However, this interaction is theoretical and has not been reported in the
medical literature. A single case has been reported of a 34-year-old female who developed
severe nausea, vomiting, drowsiness, and heart symptoms following self-administration of
passion flower. It is not known for certain if passion flower caused her symptoms.6
Passion flower has not been proven to be safe during pregnancy and breast-feeding.
At the time of writing, there were no well-known drug interactions
with passion flower.
References:1. Foster S. Herbs for Your Health. Loveland, CO: Interweave
Press, 1996, 68–9.
2. Akhondzadeh S, Naghavi HR, Vazirian M, et al. Passionflower in the
treatment of generalized anxiety: a pilot double-blind randomized controlled trial with
oxazepam. J Clin Pharm Ther 2001;26:363–7.
3. Meier B. Passiflora incarnata L.—Passion flower:
Portrait of a medicinal plant. Zeitschrift Phytother 1995;16:115–26.
4. Wichtl M. Herbal Drugs and Phytopharmaceuticals. Boca Raton,
FL: CRC Press, 1994, 363–5.
5. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide
for Health-Care Professionals. London: Pharmaceutical Press, 1996, 206–7.
6. Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata
L. J Toxicol Clin Toxicol 2000;38:63–6.