Passionflower Tea

Safety, side effects & who should avoid it

Passionflower tea is generally well tolerated, and the NIH LiverTox database rates it an unlikely cause of liver injury. But it is not just a pleasant drink. Three cautions matter most: it can cause drowsiness, dizziness, and confusion; it is expected to add to the effects of alcohol, sedatives, and anesthesia; and NCCIH advises against it in pregnancy. It is also not a treatment for a diagnosed anxiety disorder or for insomnia. If either is a real problem for you, see a clinician rather than reaching for a stronger cup.

Who should avoid it

• Pregnant people. NCCIH advises against passionflower in pregnancy because it may induce uterine contractions.
• Anyone with surgery, a colonoscopy, or sedated dental work coming up. NCCIH warns that passionflower taken with anesthesia may slow the nervous system too much, and advises talking to your health care provider if you are taking passionflower within two weeks of a scheduled procedure. The simplest course is to stop it and tell your anesthesiologist.
• Anyone about to drive, operate machinery, or do anything else needing full alertness.
• People taking prescription sedatives, sleep medications, opioids, or muscle relaxants, unless a prescriber has approved it.
• People who are breastfeeding, and children. There is essentially no safety data for either group.
• People with a long QT interval, a history of serious heart-rhythm problems, or who take QT-prolonging medications. One case report described prolonged QTc and nonsustained ventricular tachycardia in a 34-year-old woman taking passionflower at ordinary doses, and passionflower's pharmacologic profile has raised concern about QT prolongation at large doses. A single case leaves the risk unquantified, but raise it with your cardiologist or pharmacist.
• Anyone with a known allergy to Passiflora species.

Possible side effects

• Drowsiness. NCCIH lists it as a possible effect, though two surgical trials that measured sedation directly, at doses well above a cup of tea, did not find it.
• Dizziness.
• Confusion or impaired thinking.
• Unsteadiness and poor coordination (ataxia).
• Nausea and vomiting, described in a case report at ordinary doses.
• Altered consciousness. Five people in Norway were hospitalized after taking Relaxir, a concentrated commercial passionflower preparation rather than a tea, which the report describes as intoxicating and open to misuse.
• Heart-rhythm changes, including a slowed or irregular heartbeat and QT-interval prolongation. Described in a single case report, and raised as a theoretical concern at large doses. How often this happens is unknown.
• Allergic reactions, including rash.

Medication interactions

• Alcohol: additive sedation.
• Benzodiazepines (lorazepam, alprazolam, diazepam, clonazepam) and Z-drug sleep medications (zolpidem, eszopiclone, zaleplon): additive sedation and impaired coordination.
• Opioids, barbiturates, gabapentin, pregabalin, muscle relaxants, and sedating antihistamines such as diphenhydramine: additive sedation.
• Anesthesia and perioperative medications: NCCIH flags this combination as potentially slowing the nervous system too much, and advises against passionflower before surgery unless your provider recommends it.
• Medications that prolong the QT interval — some antiarrhythmics, methadone, certain antipsychotics, and antibiotics such as azithromycin. Passionflower's pharmacologic profile has raised concern about QT prolongation at large doses, and one case report describes prolonged QTc at ordinary doses. Whether tea-strength doses add any cardiac risk is unknown. Ask your pharmacist.
• Other sedating herbs and supplements — valerian, kava, hops, chamomile, lemon balm, melatonin, CBD. Effects are expected to stack, and commercial sleep teas often contain several at once.
• Blood pressure medications: most trials found no effect of passionflower on blood pressure, and a 2025 surgical trial found slightly higher diastolic pressure in the passionflower group. Don't assume it lowers blood pressure, and don't adjust medication around it.
• Warfarin and other blood thinners: passionflower is sometimes described as containing coumarin-type compounds. There is no good human evidence of a clinically important interaction, but tell your prescriber if you drink it regularly.
• MAO inhibitors (phenelzine, tranylcypromine, selegiline) and linezolid: passionflower has been reported to contain trace harmala alkaloids, which inhibit monoamine oxidase in the laboratory. How much is present in commercial Passiflora incarnata is debated, and whether tea-strength doses matter clinically is unknown. Ask your pharmacist first.

Pregnancy & breastfeeding

Don't drink passionflower tea while pregnant. NCCIH advises against it because it may induce uterine contractions, and no trial has tested whether that concern holds at tea-strength doses. For breastfeeding there is almost no data at all — not reassuring data, simply none — so avoid it, or talk to your doctor first.

How much is too much

No established upper limit. NCCIH says passionflower may be safe as a tea for up to about seven nights, and that daily use of passionflower extract may be safe for up to eight weeks; beyond that, nobody has studied it. The one positive tea trial used a single cup per night for one week. One evening cup is a reasonable ceiling — and needing it every night is a reason to see a doctor about your sleep, not to drink more tea. Bear in mind, too, that herbal sleep products are loosely regulated: a 2026 review of sedative herbal supplements identified adulteration and undeclared ingredients as a genuine risk in this category, and the most serious harms reported in the literature involved concentrated preparations, not tea.