Passionflower is often presented as a “natural” solution for stress and sleep disorders… but “natural” doesn’t mean “safe.” If you’re searching for information about passionflower’s safety , it’s usually for a simple reason: to know if you can take it safely, especially if you’re on medication, pregnant, breastfeeding, or if you need to drive.

In this guide, you will understand the real risks, contraindications, interactions to be aware of, and the right reflexes to use it responsibly.

Is passionflower dangerous? 

In most healthy adults, passionflower (often Passiflora incarnata ) is generally well tolerated at recommended doses, with relatively rare side effects. However, it can become problematic in three situations:

• Drowsiness / decreased alertness (danger driving, machinery).
• Interactions with certain medications (sedatives/psychotropics, anticoagulants, etc.).
• Populations at risk : pregnancy, breastfeeding, children, liver disease.

Mainstream medical sources mainly emphasize caution regarding sedation and interactions, as well as avoidance during pregnancy/breastfeeding.

Possible side effects of passionflower (what can actually happen)

The most frequent side effects (although they remain rare)

Reported side effects are rare, but may include:

• Nausea, digestive problems, vomiting
• Allergic reactions (e.g., allergic rhinitis)
• Drowsiness / decreased alertness (an expected but bothersome effect)

More unusual effects reported

Isolated cases have been reported in some reference documents for passionflower-based medicines:

• Hypersensitivity (e.g., angiitis)
• Nausea + tachycardia (rapid heartbeat)

Taking the drug can also impair the ability to drive.

The most tangible “danger”: drowsiness and decreased alertness

This is the most important point in practice: passionflower is used for its calming/sedative effects, so it can reduce alertness, cause drowsiness and increase the risk of accidents if you are driving or operating machinery.

Pro tip (safety) : if you are testing passionflower for the first time, do it on an evening without driving, to assess your individual sensitivity.

Contraindications: Who should not take passionflower?

Pregnancy: not recommended (precautionary principle)

Passionflower is generally not recommended during pregnancy , as there is insufficient human data to rule out a risk (and uterine contractions have been observed in animals).

Breastfeeding: not recommended

The same logic applies: lack of data and the possibility of active substances passing into breast milk. Its use is generally discouraged during breastfeeding .

Children: caution is advised; it is often not recommended before the age of 12

Its use is frequently discouraged in children (often before the age of 12). Note: some medications may have pediatric indications according to their marketing authorization, which does not mean that all over-the-counter forms are suitable.

Allergy / Hypersensitivity

Classic contraindication: allergy to passionflower → avoid.

Liver disease / hepatotoxic treatments: avoid without medical advice

In case of liver disease or taking potentially hepatotoxic , medical advice is essential (avoid self-medication).

Drug interactions: the real “hidden danger” of passionflower

Interaction #1: Sedatives / psychiatric medications

Because it has a sedative effect, passionflower can increase drowsiness if combined with:

• Sleeping pills (including benzodiazepines)
• Tranquilizers / anxiolytics
• Antidepressants
• Antiepileptics
• Neuroleptics / antipsychotics
• Pain relievers or cough suppressants derived from opium

Common mistake : combining passionflower + calming plants (valerian, hops, lemon balm…) + an anxiolytic → additive sedative effects.

Interaction #2: alcohol

Alcohol already increases sedation: it is recommended to avoid alcohol (drowsiness/alertness).

Interaction #3: Anticoagulants / risk of bleeding

Passionflower may increase the effect of anticoagulants and therefore increase the risk of bleeding: medical advice before taking.

Interaction #4: association with other sedatives

If used in conjunction with other sedatives, medical advice is recommended.

Summary table “Passionflower danger” (to scan in 10 seconds)

How to use passionflower while minimizing risks (expert protocol)

1) Choose a “controllable” form

• Herbal medicinal product (AMM) : dosage and precautions are regulated (leaflet/SmPC).
• Dietary supplement : variable quality; beware of the accumulation of sedative plants in “sleep” formulas.
• Infusion / loose plant : dosage less standardized (more difficult to anticipate the effect).

2) Start low, observe, don't accumulate

1. Start with the minimum dose recommended on the product.
2. First take in the evening , with no driving planned.
3. Do not initially combine with alcohol, valerian, hops, lemon balm, etc.
4. If daytime sleepiness occurs: reduce dosage, shift to evening, or stop.

3) Limit the duration and reassess

In practice, it is best to avoid exceeding 4 weeks without medical advice; if there is no effect, a consultation is necessary.

4) Warning signs: when to stop and seek medical help

Stop and seek medical advice if you observe:

• Allergic reaction (hives, respiratory distress, severe rhinitis)
• Unusual palpitations / discomfort
• Severe drowsiness, confusion
• Abnormal bleeding if you are taking anticoagulants

FAQ 

Is passionflower dangerous?

It is generally well tolerated, but the main danger of passionflower is drowsiness (driving) and interactions (sedatives/psychotropics, anticoagulants).

What are the side effects of passionflower?

They are rare but mainly include nausea/digestive disorders, allergic reactions, and decreased alertness related to the sedative effect.

Is it safe to take passionflower while pregnant?

As a precaution, passionflower is not recommended during pregnancy (insufficient data, contractions observed in animals).

Is it safe to take passionflower while breastfeeding?

It is not recommended in the absence of data on its passage into breast milk.

Does passionflower interact with antidepressants or anxiolytics?

Yes, it can increase drowsiness when combined with sedative medications (anxiolytics, sleeping pills, antidepressants, antiepileptics). Medical advice is recommended.

Is it safe to drive after taking passionflower?

Caution: Passionflower can impair alertness and make driving dangerous, especially at first or in combination with other sedatives.

How long can you take passionflower?

In practice, it is best to avoid exceeding 4 weeks without medical advice; if it does not work, the cause of the sleep/anxiety disorders must be reassessed.

Conclusion

The danger of passionflower lies not so much in sudden toxicity in healthy adults, but primarily in drowsiness, decreased alertness, and drug interactions (particularly with sedatives/psychotropic drugs and anticoagulants). It is not recommended during pregnancy and breastfeeding, and caution is advised in children and in cases of liver disease.

If you are taking medication (for sleep, anxiety, depression, epilepsy, or as an anticoagulant) or if you are pregnant/breastfeeding, the best course of action is: do not add it alone and seek medical/pharmacist advice before starting.