Herbadex

Herb–Drug Interactions & Safety Matrix

Known drug interactions, pregnancy/breastfeeding status, minimum age limits and external-only warnings from published monographs.

123 herbs

Safety Matrix
All herbs	Strongest evidence	Pregnancy	Breastfeeding	Children	Drug interactions
Alder Buckthorn BarkFrangula alnus	A Strong clinical evidence	Avoid	Avoid	Avoid	Major Cardiac glycosides (e.g. digoxin), antiarrhythmics, QT-prolonging medicines: Low potassium from long-term use can increase their effects; ask a doctor first. Moderate Diuretics, corticosteroids, liquorice root: May increase potassium loss; ask a doctor first.
AllspicePimenta dioica	T Traditional use	Generally safe	Generally safe	Generally safe	Minor Anticoagulants (large amounts): Eugenol may affect platelets; does not apply to food amounts.
AnisePimpinella anisum	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Argan OilArgania spinosa	C Laboratory / animal evidence	Generally safe	Generally safe	Caution	No recorded interactions
ArnicaArnica montana⚠ External use only	T Traditional use	Avoid	Unknown	Avoid	No recorded interactions
Artichoke LeafCynara cardunculus (syn. C. scolymus)	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
BasilOcimum basilicum	T Traditional use	Caution	Caution	Caution	Minor Warfarin: Very high intakes may reduce its effect because of vitamin K; keep daily intake steady.
Bay LeafLaurus nobilis	T Traditional use	Caution	Caution	Caution	Minor Diabetes medicines: Large amounts may affect blood sugar. Minor Sedatives: Large amounts may add to drowsiness (theoretical).
Birch LeafBetula pendula, Betula pubescens	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Bitter Melon in Olive OilMomordica charantia	B Limited clinical evidence	Avoid	Avoid	Avoid	Major Diabetes medicines and insulin: May further lower blood sugar and cause hypoglycaemia.
Black Mulberry SyrupMorus nigra	T Traditional use	Generally safe	Generally safe	Caution	No recorded interactions
Black PepperPiper nigrum	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	Moderate High-dose piperine supplements with phenytoin, propranolol, theophylline, ciclosporin: May raise drug levels; does not apply to food amounts.
Black SeedNigella sativa	B Limited clinical evidence	Caution	Caution	Caution	Moderate Diabetes medicines: May further lower blood sugar. Minor Blood pressure medicines: May further lower blood pressure. Minor Anticoagulants: High doses could theoretically raise bleeding risk.
Black Seed OilNigella sativa	B Limited clinical evidence	Avoid	Caution	Caution	Moderate Diabetes medicines: May further lower blood sugar. Minor Anticoagulants: Could theoretically raise bleeding risk. Minor Blood pressure medicines: May further lower blood pressure.
Black TeaCamellia sinensis	A Strong clinical evidence	Caution	Caution	Caution	Moderate Iron supplements: Reduces absorption; leave 1–2 hours apart. Minor Other caffeinated products, stimulant drugs: Caffeine effects may add up. Minor Lithium, clozapine, theophylline: Caffeine may affect their levels.
Blue Anemone FlowerAnemone spp.⚠ External use only	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Broadleaf PlantainPlantago major	T Traditional use	Avoid	Avoid	Caution	Minor Medicines taken at the same time: Mucilage may delay absorption; leave 30–60 minutes apart.
Buckthorn SeedRhamnus cathartica	T Traditional use	Avoid	Avoid	Avoid	Major Cardiac glycosides (e.g. digoxin), antiarrhythmics: Low potassium can increase their effects and side effects. Moderate Diuretics, corticosteroids, liquorice root: May increase potassium loss.
Cajun SeasoningCapsicum annuum, Piper nigrum, Allium sativum	T Traditional use	Generally safe	Generally safe	Caution	No recorded interactions
CalendulaCalendula officinalis⚠ External use only	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
CardamomElettaria cardamomum	T Traditional use	Generally safe	Generally safe	Caution	No recorded interactions
Castor OilRicinus communis	A Strong clinical evidence	Avoid	Avoid	Avoid	Moderate Cardiac glycosides, diuretics: Potassium loss increases interaction risk. Minor All oral medicines: Rapid gut transit may reduce absorption.
CentauryCentaurium erythraea	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
ChamomileMatricaria recutita	T Traditional use	Generally safe	Generally safe	Caution	Moderate Medicines taken after organ transplantation: Interactions via liver enzymes (CYP450) were reported with long-term, high-dose oral use.
Chasteberry SeedVitex agnus-castus	A Strong clinical evidence	Avoid	Avoid	Avoid	Moderate Dopamine agonists and antagonists, oestrogens and anti-oestrogens: Interactions cannot be excluded because of possible dopamine-like and oestrogenic effects; ask a doctor first.
Chebulic MyrobalanTerminalia chebula	T Traditional use	Avoid	Avoid	Avoid	Minor Iron supplements and medicines taken at the same time: Tannins may reduce absorption; leave 2 hours apart. Minor Diabetes medicines: Lowered blood sugar in animal studies.
Cherry StemPrunus avium	T Traditional use	Avoid	Avoid	Avoid	Moderate Diuretic medicines, lithium: May affect fluid and salt balance.
CinnamonCinnamomum verum	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
CloveSyzygium aromaticum	T Traditional use	Generally safe	Generally safe	Caution	Minor Anticoagulants (large amounts): Eugenol may affect platelets; does not apply to food amounts.
Clove OilSyzygium aromaticum⚠ External use only	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Coconut OilCocos nucifera	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	No recorded interactions
CorianderCoriandrum sativum	T Traditional use	Generally safe	Generally safe	Generally safe	Minor Diabetes medicines (concentrated extract): May further lower blood sugar (animal data).
Corn SilkZea mays	T Traditional use	Avoid	Avoid	Avoid	Moderate Diuretic medicines, lithium: May affect fluid and salt balance. Minor Diabetes and blood pressure medicines: Lowered blood sugar and blood pressure in animal studies.
Costus RootSaussurea costus	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Couch GrassElymus repens	T Traditional use	Avoid	Avoid	Avoid	Moderate Diuretic medicines, lithium: May affect fluid and salt balance; ask a doctor before combining.
Cubeb PepperPiper cubeba	T Traditional use	Avoid	Caution	Caution	No recorded interactions
CuminCuminum cyminum	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	Minor Diabetes medicines (concentrated extract): May further lower blood sugar.
Curry PowderCurcuma longa, Coriandrum sativum, Cuminum cyminum, Trigonella foenum-graecum	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions
Dandelion LeafTaraxacum officinale	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Devil's ClawHarpagophytum procumbens, H. zeyheri	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
EchinaceaEchinacea purpurea	A Strong clinical evidence	Avoid	Avoid	Avoid	No recorded interactions
ElderflowerSambucus nigra	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
EleutheroEleutherococcus senticosus	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Eucalyptus OilEucalyptus globulus⚠ External use only	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
FennelFoeniculum vulgare	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
FenugreekTrigonella foenum-graecum	T Traditional use	Avoid	Avoid	Avoid	Moderate Diabetes medicines: Monitor blood sugar closely because of a possible blood-sugar-lowering effect.
Ferula Root WaterFerula spp.	C Laboratory / animal evidence	Avoid	Avoid	Avoid	Moderate Drugs such as sildenafil, tadalafil and nitrates: Possible added effect on blood pressure; do not combine. Moderate Anticoagulants: Its coumarins could theoretically increase bleeding risk.
FlaxseedLinum usitatissimum	A Strong clinical evidence	Avoid	Avoid	Avoid	Moderate Other oral medicines: Absorption may be delayed; leave at least 30–60 minutes between them and flaxseed. Moderate Medicines that slow the bowel (e.g. opioids, loperamide): Use together only under medical supervision because of the risk of bowel obstruction.
Frankincense (Olibanum)Boswellia sacra / Boswellia serrata	B Limited clinical evidence	Avoid	Avoid	Avoid	Moderate Anticoagulants (e.g. warfarin): Limited data suggest it may increase bleeding risk; ask a doctor before combining.
FumitoryFumaria officinalis	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
GarlicAllium sativum	T Traditional use	Avoid	Avoid	Avoid	Moderate Anticoagulants and antiplatelet medicines (e.g. warfarin, clopidogrel): May prolong bleeding time; use with care and with your doctor's knowledge. Major Saquinavir/ritonavir (HIV medicines): May lower drug levels and cause loss of effect; must not be used together.
GingerZingiber officinale	A Strong clinical evidence	Avoid	Avoid	Caution	No recorded interactions
Ginkgo LeafGinkgo biloba	A Strong clinical evidence	Avoid	Avoid	Avoid	Major Anticoagulants (e.g. warfarin) and antiplatelet drugs (e.g. clopidogrel, aspirin, other NSAIDs): Their effect may change and bleeding risk may rise; medical monitoring needed. Major Efavirenz (HIV medicine): Its levels may fall; combined use is not recommended. Moderate Dabigatran: Levels may rise via gut P-glycoprotein inhibition; use with caution. Moderate Nifedipine: Levels may rise; dizziness and hot flushes may get worse.
Green ClayMontmorillonite / Illite (mineral)⚠ External use only	C Laboratory / animal evidence	Caution	Caution	Caution	Major All medicines, if swallowed: Clay binds medicines and blocks their absorption.
Green TeaCamellia sinensis	T Traditional use	Avoid	Avoid	Avoid	Moderate Sedative medicines: Caffeine may reduce the effect of sedatives. Moderate Sympathomimetic medicines (e.g. some decongestants): Caffeine may increase their side effects.
HawthornCrataegus spp.	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Heather LeafCalluna vulgaris / Erica spp.	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
HibiscusHibiscus sabdariffa	B Limited clinical evidence	Avoid	Caution	Caution	Moderate Blood pressure medicines: May further lower blood pressure. Minor Hydrochlorothiazide: May change its effect; ask a doctor before combining. Minor Chloroquine (malaria drug): May reduce its absorption.
HopsHumulus lupulus	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Horse ChestnutAesculus hippocastanum	A Strong clinical evidence	Avoid	Avoid	Avoid	No recorded interactions
HorsetailEquisetum arvense	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Isot PepperCapsicum annuum	T Traditional use	Generally safe	Caution	Caution	No recorded interactions
Isparta Rose WaterRosa damascena	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions
Ivy LeafHedera helix	A Strong clinical evidence	Avoid	Avoid	Caution	No recorded interactions
Korean GinsengPanax ginseng	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Lady's MantleAlchemilla vulgaris	T Traditional use	Avoid	Avoid	Caution	Minor Iron supplements and medicines taken at the same time: Tannins may reduce absorption; leave 2 hours apart.
LavenderLavandula angustifolia	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Lavender OilLavandula angustifolia⚠ External use only	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Lemon BalmMelissa officinalis	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Licorice RootGlycyrrhiza glabra	T Traditional use	Avoid	Avoid	Avoid	Major Diuretics, cardiac glycosides (e.g. digoxin), corticosteroids, stimulant laxatives (e.g. senna): May increase potassium loss and electrolyte imbalance; do not combine. Moderate Blood pressure medicines: May reduce their blood-pressure-lowering effect. Moderate Medicines broken down by CYP3A4 (e.g. midazolam, omeprazole): May slightly lower their blood levels; take care when combining.
LindenTilia cordata, Tilia platyphyllos	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
MahlabPrunus mahaleb	T Traditional use	Generally safe	Generally safe	Generally safe	Minor Warfarin (large amounts): Its coumarin could theoretically interact; does not apply to food amounts.
Marshmallow RootAlthaea officinalis	T Traditional use	Avoid	Avoid	Caution	Minor Other oral medicines: Absorption may be delayed; leave at least 30–60 minutes between them and marshmallow root.
Mastic GumPistacia lentiscus	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Milk ThistleSilybum marianum	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
MintMentha × piperita	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
Mustard SeedBrassica spp. / Sinapis alba	T Traditional use	Caution	Caution	Avoid	No recorded interactions
NutmegMyristica fragrans	T Traditional use	Avoid	Caution	Avoid	Moderate Sedatives and psychiatric medicines: Nervous system effects may increase at high amounts.
Okra SeedAbelmoschus esculentus	C Laboratory / animal evidence	Caution	Caution	Caution	Minor Diabetes medicines: May further lower blood sugar (animal data). Minor Metformin: Okra mucilage reduced metformin absorption in animals; do not take at the same time.
Passion FlowerPassiflora incarnata	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Pelargonium RootPelargonium sidoides, Pelargonium reniforme	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
Peppermint OilMentha × piperita	A Strong clinical evidence	Avoid	Avoid	Avoid	Minor Acid-reducing medicines (antacids, H2 blockers, proton pump inhibitors) and food: Can dissolve the capsule coating too early; do not take at the same time.
Pine Cone SyrupPinus spp.	T Traditional use	Caution	Caution	Caution	No recorded interactions
Poppy SeedPapaver somniferum	C Laboratory / animal evidence	Generally safe	Generally safe	Caution	No recorded interactions
Psyllium HuskPlantago ovata	A Strong clinical evidence	Caution	Caution	Caution	Moderate Minerals, vitamin B12, heart glycosides (e.g. digoxin), coumarin anticoagulants, carbamazepine, lithium: Absorption may be delayed; leave at least 30–60 minutes between them and psyllium. Moderate Diabetes medicines: Diabetes treatment may need adjusting; use only under medical supervision. Moderate Thyroid hormones: The thyroid hormone dose may need adjusting; use under medical supervision. Moderate Medicines that slow the bowel (e.g. opioids): Use together only under medical supervision because of the risk of bowel obstruction.
Pumpkin SeedCucurbita pepo	T Traditional use	Caution	Caution	Avoid	No recorded interactions
Red Pepper FlakesCapsicum annuum	A Strong clinical evidence	Generally safe	Caution	Caution	No recorded interactions
RhodiolaRhodiola rosea	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Ribwort PlantainPlantago lanceolata	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
Rose HipRosa canina	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	Minor Warfarin (high doses): High-dose vitamin C may alter its effect. Minor Lithium: Its diuretic effect may affect lithium excretion.
Rose OilRosa damascena⚠ External use only	B Limited clinical evidence	Caution	Caution	Caution	No recorded interactions
RosemarySalvia rosmarinus (syn. Rosmarinus officinalis)	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
SaffronCrocus sativus	B Limited clinical evidence	Avoid	Caution	Avoid	Moderate Antidepressants: Possible added effect; ask a doctor before combining. Minor Blood pressure medicines and anticoagulants: High doses may lower blood pressure and increase bleeding.
SageSalvia officinalis	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Sandy EverlastingHelichrysum arenarium	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Saw PalmettoSerenoa repens	A Strong clinical evidence	Unknown	Unknown	Avoid	Moderate Warfarin: Raised INR has been reported in a few cases; monitor INR closely.
SennaSenna alexandrina	A Strong clinical evidence	Avoid	Avoid	Avoid	Major Cardiac glycosides (e.g. digoxin), antiarrhythmics, QT-prolonging medicines: Low potassium from long-term use can increase their effects; ask a doctor first. Moderate Diuretics, corticosteroids, liquorice root: May increase potassium loss; ask a doctor first.
SesameSesamum indicum	B Limited clinical evidence	Generally safe	Generally safe	Caution	Minor Blood pressure and diabetes medicines: Large amounts may further lower blood pressure and blood sugar.
Small-Flowered WillowherbEpilobium parviflorum	T Traditional use	Unknown	Unknown	Avoid	No recorded interactions
Spanish LavenderLavandula stoechas	T Traditional use	Avoid	Avoid	Avoid	Moderate Sedatives and sleeping pills: May add to drowsiness.
Spirulina PowderArthrospira platensis	B Limited clinical evidence	Caution	Caution	Caution	Moderate Immunosuppressants: May reduce their effect by stimulating immunity. Minor Anticoagulants: Could theoretically raise bleeding risk.
St. John's WortHypericum perforatum	A Strong clinical evidence	Avoid	Avoid	Avoid	Major Birth control pills and other hormonal contraceptives: Lowers their levels and can cause breakthrough bleeding and reduced protection; use an extra method. Major Coumarin anticoagulants (e.g. warfarin), ciclosporin, tacrolimus, everolimus, sirolimus: Lowers their blood levels; combined use is contraindicated. Major HIV medicines (protease inhibitors, nucleoside reverse transcriptase inhibitors) and some cancer drugs (e.g. irinotecan, imatinib): Reduces their effect; combined use is contraindicated. Major Antidepressants (e.g. sertraline, paroxetine) and buspirone: Risk of serotonin syndrome (sweating, fast heartbeat, fever, agitation, tremor); do not combine. Moderate Alprazolam, diazepam, midazolam, methadone, simvastatin, digoxin, amitriptyline and other drugs broken down by CYP enzymes: Their levels may fall; ask a doctor first if you take prescription medicines.
St. John's Wort OilHypericum perforatum⚠ External use only	T Traditional use	Avoid	Avoid	Caution	No recorded interactions
Stinging NettleUrtica dioica, Urtica urens	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
SumacRhus coriaria	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	Minor Diabetes medicines: May further lower blood sugar.
Sweet Almond OilPrunus dulcis	B Limited clinical evidence	Generally safe	Generally safe	Generally safe	No recorded interactions
Tea Tree OilMelaleuca alternifolia⚠ External use only	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Terebinth BerryPistacia terebinthus	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions
Terebinth SoapPistacia terebinthus⚠ External use only	T Traditional use	Generally safe	Generally safe	Caution	No recorded interactions
ThymeThymus vulgaris, Thymus zygis	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Thyme OilThymus vulgaris	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Tonka BeanDipteryx odorata	T Traditional use	Avoid	Avoid	Avoid	Moderate Anticoagulants (e.g. warfarin): Coumarin carries a theoretical interaction risk. Moderate Liver-stressing medicines (e.g. high-dose paracetamol, some statins): May increase the risk of liver damage.
TribulusTribulus terrestris	B Limited clinical evidence	Avoid	Avoid	Avoid	Moderate Diabetes medicines: May lower blood sugar; monitor it. Moderate Blood pressure medicines, lithium: May lower blood pressure; may affect lithium excretion.
TurmericCurcuma longa	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Valerian RootValeriana officinalis	A Strong clinical evidence	Avoid	Avoid	Avoid	No recorded interactions
Vanilla BeanVanilla planifolia	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions
Vine LeafVitis vinifera	A Strong clinical evidence	Avoid	Avoid	Avoid	No recorded interactions
Willow BarkSalix spp.	A Strong clinical evidence	Avoid	Avoid	Avoid	Major Anticoagulants (e.g. coumarin derivatives such as warfarin): May increase the effect of anticoagulants; do not combine without medical advice. Moderate Aspirin and other painkillers (NSAIDs): Combined use is not recommended without medical advice.
Witch HazelHamamelis virginiana⚠ External use only	T Traditional use	Unknown	Unknown	Caution	No recorded interactions
YarrowAchillea millefolium	T Traditional use	Avoid	Avoid	Avoid	No recorded interactions
Yedi Turlu Spice BlendPiper nigrum, Pimenta dioica, Cinnamomum verum, Syzygium aromaticum, Myristica fragrans, Zingiber officinale, Elettaria cardamomum	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions
Yerba MateIlex paraguariensis	T Traditional use	Avoid	Avoid	Avoid	Moderate MAO-inhibitor antidepressants: Use with caution. Moderate Sedatives and sympathomimetic medicines: Caffeine may reduce the effect of sedatives and increase side effects of sympathomimetics.
Za'atarThymbra spicata, Rhus coriaria, Sesamum indicum	T Traditional use	Generally safe	Generally safe	Generally safe	No recorded interactions