The Everything Guide to Herbal Remedies (34 page)

Because they have medicinal properties, herbs should be considered drugs when it comes to interactions. Just as you would do (or should do) when taking prescription or OTC pharmaceuticals, you should make sure that the herbs you’re taking aren’t interfering with any drugs—or with each other.

Several herbs act as sedatives (they induce relaxation and sleepiness) and can have an additive effect—that is, they’ll increase the action of another agent—when combined with other sedatives, including alcohol.

Don’t combine sedating drugs like antihistamines (including those in antimotion-sickness meds) or insomnia remedies with herbs like gotu kola
(Centella asiatica),
kava
(Piper methysticum),
or valerian
(Valeriana officinalis),
which are sedating on their own. Other sedating herbs include:

• Ashwagandha
(Withania somnifera)

• Calendula
(Calendula officinalis)

• Chamomile
(Matricaria recutita)

• Eleuthero
(Eleutherococcus senticosus)

• Gotu kola
(Centella asiatica)

• Hops
(Humulus lupulus)

• Kava
(Piper methysticum)

• Lemon balm
(Melissa officinalis)

• Passionflower
(Passiflora incarnata)

• Sage
(Salvia officinalis, S. lavandulaefolia)

• Valerian
(Valeriana officinalis)

Several herbs contain caffeine or other chemicals that stimulate the central nervous system. They can have additive effects when combined with other stimulants. They include:

• Asian ginseng
(Panax ginseng)

• Cocoa
(Theobroma cacao)

• Coffee
(Coffea arabica)

• Guarana
(Paullinia cupana)

• Mate
(Ilex paraguariensis)

• Tea
(Camellia sinensis)

Several herbs work to lower glucose levels, but they can reduce blood sugar too much when combined with diabetes drugs, which do the same thing. Herbs with hypoglycemic potential include:

• Alfalfa
(Medicago sativa)

• Aloe
(Aloe vera),
when used internally

• Asian ginseng
(Panax ginseng)

• Bilberry
(Vaccinium myrtillus)

• Cinnamon
(Cinnamomum verum, C. aromaticum)

• Eleuthero
(Eleutherococcus senticosus)

• Eucalyptus
(Eucalyptus globulus)

• Fenugreek
(Trigonella foenum-graecum)

• Flax
(Linum usitatissimum)

• Ginger
(Zingiber officinale)

• Horse chestnut
(Aesculus hippocastanum)

• Konjac
(Amorphophallus konjac, A. rivieri)

• Kudzu
(Pueraria lobata)

• Nettle
(Urtica dioica)

• Onion
(Allium cepa)

• Sage
(Salvia officinalis, S. lavandulaefolia)

• Tinospora
(Tinospora cordifolia)

Several herbs exert a direct effect on heart function, and so should be avoided by anyone with a heart condition (or anyone taking drugs to treat a heart condition). These include:

• Asian ginseng
(Panax ginseng)

• Devil’s claw
(Harpagphytum procumbens)

• Danshen
(Salvia miltiorrhiza)

• Coleus
(Coleus forskohlii, Plectranthus barbatus)

• Hawthorn
(Crataegus monogyna, C. oxyacantha)

Several herbs affect platelet aggregation, or clotting of your blood, and so should be avoided if you’re taking medicines that do the same thing, such as clopidogrel (Plavix) and warfarin (Coumadin). You should discontinue using them at least two weeks before any surgery. They include:

• Andrographis
(Andrographis paniculata)

• Asian ginseng
(Panax ginseng)

• Borage
(Borago officinalis)

• Cayenne
(Capsicum annuum, C. frutescens)

• Chamomile
(Matricaria recutita)

• Coleus
(Coleus forskohlii, Plectranthus barbatus)

• Danshen
(Salvia miltiorrhiza)

• Dong quai
(Angelica sinensis)

• Eleuthero
(Eleutherococcus senticosus)

• Evening primrose
(Oenothera biennis)

• Fenugreek
(Trigonella foenum-graecum)

• Feverfew
(Tanacetum parthenium)

• Flax
(Linum usitatissimum)

• Garlic
(Allium sativum)

• Ginger
(Zingiber officinale)

• Ginkgo
(Ginkgo biloba)

• Horse chestnut
(Aesculus hippocastanum)

• Kudzu
(Pueraria lobata)

• Licorice
(Glycyrrhiza glabra)

• Onion
(Allium cepa)

• Pineapple
(Ananas comosus)

• Red clover
(Trifolium pratense)

• Reishi
(Ganoderma lucidum)

• Turmeric
(Curcuma longa)

• Willow
(Salix alba)

Some herbs contain chemicals called
phytoestrogens
that act like the human hormone estrogen. Others affect estrogen levels through different mechanisms. Generally speaking, pregnant and nursing women, men, and children should avoid them, as should anyone with a hormone-dependent disease or condition. You also should use caution when combining them with oral contraceptives. They include:

• Alfalfa
(Medicago sativa)

• Black cohosh
(Actaea racemosa, Cimicifuga racemosa)

• Dong quai
(Angelica sinensis)

• Flax
(Linum usitatissimum)

• Kudzu
(Pueraria lobata)

• Red clover
(Trifolium pratense)

• Saw palmetto
(Serenoa repens)

• Soy
(Glycine max)

• Vitex
(Vitex agnus-castus)

Some herbs can affect your immune system, and therefore shouldn’t be combined with immunosuppressant drugs. They include:

• Alfalfa
(Medicago sativa)

• Andrographis
(Andrographis paniculata)

• Ashwagandha
(Withania somnifera)

• Astragalus
(Astragalus membranaceus)

• Cat’s claw
(Uncaria guianensis, U. tomentosa)

• Cordyceps
(Cordyceps sinensis)

• Elderberry
(Sambucus nigra)

• Eleuthero
(Eleutherococcus senticosus)

• Maritime pine
(Pinus pinaster)

• Neem
(Azadirachta indica)

• Reishi
(Ganoderma lucidum)

• Tinospora
(Tinospora cordifolia)

Some herbs increase immune function, and shouldn’t be taken by people with autoimmune disorders:

• Barberry
(Berberis vulgaris)

• Echinacea
(Echinacea purpurea)

• Goldenseal
(Hydrastis canadensis)

• Tinospora
(Tinospora cordifolia)

Several herbs work to lower cholesterol—and can increase the effect of pharmaceuticals that do the same; they also can skew laboratory lipid test results. They include:

• Alfalfa
(Medicago sativa)

• Flax
(Linum usitatissimum)

• Garlic
(Allium sativum)

• Guggul
(Commiphora wightii, C. mukul)

• Hawthorn
(Crataegus monogyna, C. oxyacantha)

• Oat
(Avena sativa)

• Psyllium
(Plantago ovata, P. psyllium)

Several herbs have hypotensive effects and so shouldn’t be combined with other blood pressure-lowering agents. They include:

• Andrographis
(Andrographis paniculata)

• Cat’s claw
(Uncaria guianensis, U. tomentosa)

• Coleus
(Coleus forskohlii, Plectranthus barbatus)

• Garlic
(Allium sativum)

• Nettle
(Urtica dioica)

• Olive
(Olea europaea)

• Pomegranate
(Punica granatum)

• Reishi
(Ganoderma lucidum)

• Valerian
(Valeriana officinalis)

• Hawthorn
(Crataegus monogyna, C. oxyacantha)

Others can cause a rise in blood pressure. They include:

• Licorice
(Glycyrrhiza glabra)

• Sage
(Salvia officinalis, S. lavandulaefolia)

• Yohimbe
(Pausinystalia yohimbe)

Some herbs can adversely affect liver function—they’re potentially hepatotoxic—and shouldn’t be used concurrently. They also shouldn’t be combined with hepatotoxic pharmaceuticals such as acetaminophen (Tylenol). These agents can also interfere with liver function tests and might exacerbate liver problems in some people. Herbs that can affect liver function include:

• Black cohosh
(Actaea racemosa, Cimicifuga racemosa)

• Borage
(Borago officinalis)

• Butterbur
(Petasites hybridus)

• Cinnamon
(Cinnamomum verum, C. aromaticum)

• Comfrey
(Symphytum officinale)

• Gotu kola
(Centella asiatica)

• Kava
(Piper methysticum)

Several medicinal herbs belong to botanical families that, unfortunately, can cause allergies in some people. The
Asteraceae/Compositae
family contains many medicinal plants—and a few common allergens. If you’re allergic to ragweed, marigolds, or daisies, avoid these herbs: