Table 1.

Key safety issues^a

St John's wort	Ginkgo	Asian ginseng	Garlic	Echinacea
Precautions
Sensitivity to sunlight	Increased bleeding risk	People with diabetes should use extra caution, especially if using medicines to lower blood sugar or taking other herbs ... also thought to lower blood sugar.	Can thin the blood	Allergy to related plants in daisy family
	Bleeding disorders		Use with caution if planning to have surgery or dental work.	People with asthma or atopy may be more likely to have an allergic reaction.
	Scheduled surgery or dental procedures		Use with caution if you have a bleeding disorder.
Interactions
Antidepressants	Anticoagulant drugs		Interferes with effectiveness of saquinavir, a drug used to treat HIV
Oral contraceptives
Digoxin
Indinavir and possibly other HIV medications
Irinotecan and possibly other anticancer drugs
Seizure control drugs
Warfarin and related anticoagulants
Cyclosporine
Side effects
Anxiety	Headache	Headache	Breath and body odour	Allergic reactions including rashes
Dry mouth	Nausea	Sleep problems	Heartburn	Increased asthma
Dizziness	Gastrointestinal upset	Gastrointestinal problems	Upset stomach	Anaphylaxis
Gastrointestinal symptoms	Diarrhoea	Allergic reactions	Allergic reactions	Gastrointestinal side effects
Fatigue	Dizziness	Breast tenderness
Headache	Allergic skin reactions	Menstrual irregularities
Sexual dysfunction	More severe allergic reactions occasionally reported	High blood pressure

^aAs identified in the NCCAM Herbs at a Glance monographs [13].