Table 1

Examples of popular herbal medicines* and associated risks

Common nameLatin nameIndicationAdverse effectsPotential interactions with
*All examples are of well documented efficacy (data extracted from Ernst et al3).
Garlic Allium sativum Raised blood cholesterolAllergic reactions, nausea, heartburnAnticoagulants, antidiabetics
HawthornCrataegus sppHeart failureNausea, dizziness, fatigueCardiac glycosides, antihypertensives, nitrates
Horse chestnut Aesculus hippocastanum Varicose veinsPruritus, nausea, gastrointestinal symptomsAnticoagulants
Kava Piper methysticum Forster AnxietyLiver damageDrugs acting on CNS
Maidenhair tree Ginkgo biloba Dementia, peripheral vascular diseaseGastrointestinal symptoms, diarrhoea, vomiting, allergic reactionsAnticoagulants
Saw palmetto Serenoa repens Bartram Benign prostate hyperplasiaGastrointestinal complaints, dysuria, decreased libidoHormonal drugs
St John’s wortHypericum perforatumMild/moderate depressionGastrointestinal symptoms, allergic reactions, fatigueAll drugs metabolised by cytochrome P450 enzyme system