This list below isn’t exhaustive, but it provides some examples of how certain herbs can alter the activity of certin drugs.
HERB
Bromelain
EFFECT
Increase risk of bleeding when taken with blood thinners.
HERB
Echinacea
EFFECT
May counteract immune suppressive drugs.
HERB
Garlic, Ginkgo
EFFECT
May increase the effects of blood thinners.
HERB
Ginseng
EFFECT
May worsen the side effects of stimulants.
HERB
Hawthorn
EFFECT
May increase the action of some heart medicines and decrease their side effects.
HERB
High tanin herbs such as black or green tea, bearberry, witch hazel, black walnut husk, and rasberry leaves.
EFFECT
Reduce the absorption of most drugs.
HERB
High berberine herbs such as oregon graperoot and barberry and goldenseal
EFFECT
Counteract short-acting blood thinners
HERB
High fibre herbs such as fennel seed, psyllium husk, apple pectin, flaxseed, aloe gel
EFFECT
May delay the absorption of most drugs taken at the same time.
HERB
Licorice
EFFECT
May worsen the effects of drugs that cause potassium loss.
HERB
Siberian Ginseng
EFFECT
Increases the effects of antibiotics
HERB
St John’s Wort
EFFECT
May increase the effects of narcotics and some antidepressants.
HERB
Valerian
EFFECT
Increases the effects of sedatives
