Rhus aromatica leaf
Some Safe and Not-So-Safe Herbs and Their Medicinal Uses
Eric Yarnell, ND, RH(AHG)
Copyright 2020. Do not copy this text anywhere; link to it if you want to share.
Copyright 2020. Do not copy this text anywhere; link to it if you want to share.
Toxicodendron radicans (poison ivy), formerly known as Rhus toxicodendron, and related members of the Anacardiaceae family, rightly instill fear in anyone that knows about them. A group of fat-soluble compounds known as substituted catechols, and particularly the compound urushiol, in the resin of some members of the Toxicodendron genus can cause a severe, painful, pruritic, type IV hypersensitivity reaction in some people. Members of the genus Rhus do not appear to contain these irritant compounds.
Various species of Toxicodendron have and are in fact used as medicine, though there is always a risk of causing the painful rash. Many species of Rhus are also used as medicine, with little or no risk of harm. This discussion will focus on the use of herbs in both genera at physiological (non-homeopathic) doses.
Various species of Toxicodendron have and are in fact used as medicine, though there is always a risk of causing the painful rash. Many species of Rhus are also used as medicine, with little or no risk of harm. This discussion will focus on the use of herbs in both genera at physiological (non-homeopathic) doses.
Poison Ivy and Its Cousins as Medicine
Poison ivy, formerly known as Rhus radicans, is today classified as Toxicodendron radicans. It clearly contains a substantial amount of urushiol and can cause poison ivy dermatitis. It's close cousins, Pacific poison oak (Toxicodendron diversilobum) and Eastern poison oak (Toxicodendron toxicarium) are very similar in this regard and should be considered interchangeable medicinally and toxicologically.
The Eclectic physicians made extensive use of low-doses of poison ivy and its relatives, as medicine. Harvey Wickes Felter, MD (1865–1927) stated that it was used primarily for burning pain, superficial neuralgia, pleurisy, and cystitis (Felter 1922). He also found it particularly helpful for morning stiffness and stiffness in general. Finley Ellingwood, MD (1852–1920) recommended it for such diverse indications as acute erysipelas, typhoid fever, scarlet fever, measles, smallpox (thank goodness this isn't a problem anymore!), rheumatoid arthritis, cough related to bronchitis, and influenza-related symptoms particularly headache. He also states that, "The use of this remedy in small doses, internally, frequently repeated with rhus poisoning, has long been advised. The experience of the editor has confirmed the belief that it is of benefit."
Two open trials have previously been reported on the use of homeopathic dilutions (so more dilute than what Ellingwood was using) to prevent poison ivy dermatitis. In the first, 455 children and adults with a history of poison ivy dermatitis were given 5 gtt qd of 3X potency rhus tox homeopathic for 6 wk starting in early March (when poison ivy starts to leaf out), and then three times weekly until the late fall (Gross 1958). Children were given just 3 gtt per dose. Reportedly 77% of participants had no poison ivy dermatitis, or it was much milder. Two people suffered GI upset from taking the rhus tox.
A much more recent trial treated 56 people (age 12–75 yr) with a history of poison ivy dermatitis with a combination of 6X and 12X potencies of rhus tox at a dose of 3 ml daily for 3 weeks then 3 ml monthly throughout the months poison ivy was in leaf (Stein and Parsons 2003). Reportedly 48% of participants had fewer and/or less severe episodes of poison ivy dermatitis, and 45% reported having no episodes of poison ivy dermatitis.
Felter used a specially-made tincture of fresh leaf of poison ivy known as Specific Medicine Rhus at a very low dose. This product was made by the Lloyd Brothers and is no longer available; it is possible processing steps were used that reduced or eliminated urushiol from this product. Felter recommended mixing 5–15 gtt of the Specific Medicine Rhus tincture in 4 oz of water, and then having the patient take 1 tsp every hour for acute situations or four time a day for chronic problems. Ellingwood similarly recommended use of Specific Medicine Rhus at a dose of 2–10 gtt in 4 oz of water. He states that a simple tincture was "not reliable" and not the same as Specific Medicine Rhus.
Oral ingestion of poison ivy and related urushiol-containing Toxicodendron species can cause a syndrome known as systemic contact dermatitis, with a severe rash breaking out all over the body (Oh, et al. 2003). It can also lead to leukocytosis and elevated serum transaminases, though these are transient. This effect is much less common than topical sensitization, and can occur in people with prior hypersensitivity to poison ivy or not. The risk of this happening must be expressed to any patient prescribed this medicine. While some may react with horror at the suggestion of using poison ivy or poison oak internally on purposes, this must be weighed against the routine and unflinching use of a wide range of pharmaceuticals with a known, high risk of severe adverse effects.
The Eclectic physicians made extensive use of low-doses of poison ivy and its relatives, as medicine. Harvey Wickes Felter, MD (1865–1927) stated that it was used primarily for burning pain, superficial neuralgia, pleurisy, and cystitis (Felter 1922). He also found it particularly helpful for morning stiffness and stiffness in general. Finley Ellingwood, MD (1852–1920) recommended it for such diverse indications as acute erysipelas, typhoid fever, scarlet fever, measles, smallpox (thank goodness this isn't a problem anymore!), rheumatoid arthritis, cough related to bronchitis, and influenza-related symptoms particularly headache. He also states that, "The use of this remedy in small doses, internally, frequently repeated with rhus poisoning, has long been advised. The experience of the editor has confirmed the belief that it is of benefit."
Two open trials have previously been reported on the use of homeopathic dilutions (so more dilute than what Ellingwood was using) to prevent poison ivy dermatitis. In the first, 455 children and adults with a history of poison ivy dermatitis were given 5 gtt qd of 3X potency rhus tox homeopathic for 6 wk starting in early March (when poison ivy starts to leaf out), and then three times weekly until the late fall (Gross 1958). Children were given just 3 gtt per dose. Reportedly 77% of participants had no poison ivy dermatitis, or it was much milder. Two people suffered GI upset from taking the rhus tox.
A much more recent trial treated 56 people (age 12–75 yr) with a history of poison ivy dermatitis with a combination of 6X and 12X potencies of rhus tox at a dose of 3 ml daily for 3 weeks then 3 ml monthly throughout the months poison ivy was in leaf (Stein and Parsons 2003). Reportedly 48% of participants had fewer and/or less severe episodes of poison ivy dermatitis, and 45% reported having no episodes of poison ivy dermatitis.
Felter used a specially-made tincture of fresh leaf of poison ivy known as Specific Medicine Rhus at a very low dose. This product was made by the Lloyd Brothers and is no longer available; it is possible processing steps were used that reduced or eliminated urushiol from this product. Felter recommended mixing 5–15 gtt of the Specific Medicine Rhus tincture in 4 oz of water, and then having the patient take 1 tsp every hour for acute situations or four time a day for chronic problems. Ellingwood similarly recommended use of Specific Medicine Rhus at a dose of 2–10 gtt in 4 oz of water. He states that a simple tincture was "not reliable" and not the same as Specific Medicine Rhus.
Oral ingestion of poison ivy and related urushiol-containing Toxicodendron species can cause a syndrome known as systemic contact dermatitis, with a severe rash breaking out all over the body (Oh, et al. 2003). It can also lead to leukocytosis and elevated serum transaminases, though these are transient. This effect is much less common than topical sensitization, and can occur in people with prior hypersensitivity to poison ivy or not. The risk of this happening must be expressed to any patient prescribed this medicine. While some may react with horror at the suggestion of using poison ivy or poison oak internally on purposes, this must be weighed against the routine and unflinching use of a wide range of pharmaceuticals with a known, high risk of severe adverse effects.
Treatment of Poison Ivy/Oak Dermatitis
Whether a patient develops poison ivy/oak dermatitis from incidental contact or from ingestion of poison ivy or oak internally as medicine, the treatment is the same. The author's experience is that a tincture of fresh Grindelia spp (gumweed) resinous preflowering capitula is most effective topically for resolving the rash, including in patients who do not respond to steroids (Canavan and Yarnell 2005). Felter recommended some very problematic medicines such as lead acetate, ferrous sulfate, and potassium permanganate, but botanically that a combination of sodium salicylate and colorless hydrastis (a product no-longer available) as well as Specific Medicine Lobelia (a Lloyd Brothers fresh plant extract of Lobelia inflata) were particularly helpful (Felter 1922). He also said that a decoction of fresh Alnus serrulata (alder) bark topically was very hopeful.
Many traditional sources discuss the use of Impatiens capensis (jewelweed) topically as a treatment for poison ivy or oak dermatitis. One small clinical trial found that directly applying a fresh plant mash of jewelweed did help relieve poison ivy dermatitis, but that soap was more effective (Abrams Motz, et al. 2012). Jewelweed crude extracts were not effective, and soaps that incorporated jewelweed extracts, though effective, were not superior to unmedicated soaps. A follow-up trial confirmed that a saponin extract specifically were effective at reducing severity of poison ivy dermatitis, as were soaps incorporating this extract (Motz, et al. 2015). However, once again, non-medicated soaps were also just as effective.
Many traditional sources discuss the use of Impatiens capensis (jewelweed) topically as a treatment for poison ivy or oak dermatitis. One small clinical trial found that directly applying a fresh plant mash of jewelweed did help relieve poison ivy dermatitis, but that soap was more effective (Abrams Motz, et al. 2012). Jewelweed crude extracts were not effective, and soaps that incorporated jewelweed extracts, though effective, were not superior to unmedicated soaps. A follow-up trial confirmed that a saponin extract specifically were effective at reducing severity of poison ivy dermatitis, as were soaps incorporating this extract (Motz, et al. 2015). However, once again, non-medicated soaps were also just as effective.
Medicinal Sumach Species
Numerous species of non-toxic Rhus are used as medicine and food around the world. Sumach is a common spice in the Middle East and North Africa and blends containing this, known as zatar (from Arabic, زَعْتَر) are fairly widely known these days. Sumach is derived from Syriac and Aramaic, by way of Arabic, meaning "red" (referring to the color of the fruit). Rhus is the ancient Greek (ῥοῦς) name of this plant and has no other known specific meaning. Though R. coriaria is a major species in the Old World, this discussion will focus on the use of the far more numerous species native to North America.
Felter recommended Rhus aromatica (fragrant sumach) root bark tinctures for enuresis, particularly in children (Felter 1922). Ellingwood appears to have agreed with the utility of this treatment (Ellingwood 1919). This is the most widespread and abundant species in the genus, found in all of North America except southern Florida. Its leaves smell of citrus when crushed, hence its common name. This is also a major differentiating feature from Toxicodendron spp, which do not have an odor when their leaves are crushed. Of course, if you're crushing leaves with bare skin, exposure to urushiol is guaranteed if present, so gloves should be worn or sticks used if one is uncertain of the identity of a trifoliate, poison ivy/oak-like plant in the wild.
Research has found that R. aromatica fruit are loaded with antioxidant activity, but this is hardly impressive as antioxidant activity is universal in all plants (Kim, et al. 1997). It was also one of the two most active plants against the animal parasite Haemonchus contortus in one study (Acharya, et al. 2014). A root extract inhibited herpes simplex-1 and -2 in vitro (Reichling, et al. 2009). In vitro it is spasmolytic for the urinary bladder (Borchert, et al. 2004).In this study, the extract was mostly effective against cholinergic-mediated spasms. Solidago virgaurea (goldenrod) was also effective at inhibiting bladder spasms in this study. A pilot open trial in 117 women found that a combination of fragrant sumach, Cucurbita pepo (pumpkin) seed, and Humulus lupulus (hops) flowers was significantly helpful at reducing symptoms of overactive bladder (Gauruder-Burmester, et al. 2019). More research is clearly warranted on this and other species in the genus.
The author has used R. glabra (smooth sumach) root bark, usually combined with other herbs, for nocturia related to benign prostatic hyperplasia and bladder irritability as well as enuresis and found it to work moderately well. It and other Rhus species are quite astringent and have a history of use orally for diarrhea and topically for mouth ulcers and gingivitis. Numerous in vitro reports confirm that it is antibacterial and antifungal (McCutechon, et al. 1992 and 1994; Saxena, et al. 1994). These effects are very likely due to tannins in the plant, and so will only be effective in the gut, in the pharynx, and on the skin, as tannins are not absorbed systemically. It does not contain urushiol. Felter's recommended doses of these internally are 5 drops to 3 ml of fluid extract tid (more frequently for acute problems). The author has used the much higher end of this dose range.
Felter recommended Rhus aromatica (fragrant sumach) root bark tinctures for enuresis, particularly in children (Felter 1922). Ellingwood appears to have agreed with the utility of this treatment (Ellingwood 1919). This is the most widespread and abundant species in the genus, found in all of North America except southern Florida. Its leaves smell of citrus when crushed, hence its common name. This is also a major differentiating feature from Toxicodendron spp, which do not have an odor when their leaves are crushed. Of course, if you're crushing leaves with bare skin, exposure to urushiol is guaranteed if present, so gloves should be worn or sticks used if one is uncertain of the identity of a trifoliate, poison ivy/oak-like plant in the wild.
Research has found that R. aromatica fruit are loaded with antioxidant activity, but this is hardly impressive as antioxidant activity is universal in all plants (Kim, et al. 1997). It was also one of the two most active plants against the animal parasite Haemonchus contortus in one study (Acharya, et al. 2014). A root extract inhibited herpes simplex-1 and -2 in vitro (Reichling, et al. 2009). In vitro it is spasmolytic for the urinary bladder (Borchert, et al. 2004).In this study, the extract was mostly effective against cholinergic-mediated spasms. Solidago virgaurea (goldenrod) was also effective at inhibiting bladder spasms in this study. A pilot open trial in 117 women found that a combination of fragrant sumach, Cucurbita pepo (pumpkin) seed, and Humulus lupulus (hops) flowers was significantly helpful at reducing symptoms of overactive bladder (Gauruder-Burmester, et al. 2019). More research is clearly warranted on this and other species in the genus.
The author has used R. glabra (smooth sumach) root bark, usually combined with other herbs, for nocturia related to benign prostatic hyperplasia and bladder irritability as well as enuresis and found it to work moderately well. It and other Rhus species are quite astringent and have a history of use orally for diarrhea and topically for mouth ulcers and gingivitis. Numerous in vitro reports confirm that it is antibacterial and antifungal (McCutechon, et al. 1992 and 1994; Saxena, et al. 1994). These effects are very likely due to tannins in the plant, and so will only be effective in the gut, in the pharynx, and on the skin, as tannins are not absorbed systemically. It does not contain urushiol. Felter's recommended doses of these internally are 5 drops to 3 ml of fluid extract tid (more frequently for acute problems). The author has used the much higher end of this dose range.
References
Abrams Motz V, Bowers CP, Mull Young L, Kinder DH (2012) "The effectiveness of jewelweed, Impatiens capensis, the related cultivar I. balsamina and the component, lawsone in preventing post poison ivy exposure contact dermatitis" J Ethnopharmacol 143(1):314–8.
Acharya J, Hildreth MB, Reese RN (2014) "In vitro screening of forty medicinal plant extracts from the United States Northern Great Plains for anthelmintic activity against Haemonchus contortus" Vet Parasitol 201(1–2):75–81.
Borchert VE, Czyborra P, Fetscher C, et al. (2004) “Extracts from Rhois [sic] aromatica and Solidaginis virgaurea inhibit rat and human bladder contraction” Naunyn Schmiedebergs Arch Pharmacol 369(3):281–6.
Canavan D, Yarnell E (2005) "Successful treatment of poison oak dermatitis treated with Grindelia spp (gumweed)" J Altern Complement Med 11(4):709–10.
Ellingwood F (1919) American Materia Medica, Pharmacognosy and Therapeutics 11th ed (Sandy, OR: Eclectic Medical Publications, reprinted 1998), available free online at Michael Moore's website, www.swsbm.com.
Felter HW (1922) Eclectic Materia Medica, Pharmacology and Therapeutics (Sandy, OR: Eclectic Medical Publications, reprinted 1998), available free online at Michael Moore's website, www.swsbm.com.
Gladman AC (2006) "Toxicodendron dermatitis: Poison ivy, oak, and sumac" Wilderness Environ Med 17(2):120–8.
Gross ER (1958) "An oral antigen preparation in the prevention of poison ivy dermatitis; results in 455 cases of ivy sensitivity" Ind Med Surg 27(3):142–4.
Gauruder-Burmester A, Heim S, Patz B, Seibt S (2019) "Cucurbita pepo-Rhus aromatica-Humulus lupulus combination reduces overactive bladder symptoms in women---a noninterventional study" Planta Med 85(13):1044–53.
Kim BJ, Kim JH, Kim HP, Heo MY (1997) "Biological screening of 100 plant extracts for cosmetic use (II): Anti-oxidative activity and free radical scavenging activity" Int J Cosmet Sci 19(6):299–307.
McCutcheon AR, Ellis SM, Hancock RE, Towers GH (1992) "Antibiotic screening of medicinal plants of the British Columbian native peoples" J Ethnopharmacol 37(3):213–23.
McCutcheon AR, Ellis SM, Hancock RE, Towers GH (1994) "Antifungal screening of medicinal plants of British Columbian native peoples" J Ethnopharmacol 44(3):157–69.
Motz VA, Bowers CP, Kneubehl AR, et al. (2015) "Efficacy of the saponin component of Impatiens capensis Meerb in preventing urushiol-induced contact dermatitis" J Ethnopharmacol 162:163-7.
Oh SH, Haw CR, Lee MH (2003) "Clinical and immunologic features of systemic contact dermatitis from ingestion of Rhus (Toxicodendron)" Contact Dermatitis 48(5):251–4.
Reichling J, Neuner A, Sharaf M, et al. (2009) "Antiviral activity of Rhus aromatica (fragrant sumac) extract against two types of herpes simplex viruses in cell culture" Pharmazie 64(8):538–41.
Saxena G, McCutcheon AR, Farmer S, et al. (1994) "Antimicrobial constituents of Rhus glabra" J Ethnopharmacol 42(2):95–9.
Stein MF, Parsons E (2003) "Effectiveness in oral rhus toxicodendron solution for poison ivy" Int J Pharm Compd 7(4):272–5.
Acharya J, Hildreth MB, Reese RN (2014) "In vitro screening of forty medicinal plant extracts from the United States Northern Great Plains for anthelmintic activity against Haemonchus contortus" Vet Parasitol 201(1–2):75–81.
Borchert VE, Czyborra P, Fetscher C, et al. (2004) “Extracts from Rhois [sic] aromatica and Solidaginis virgaurea inhibit rat and human bladder contraction” Naunyn Schmiedebergs Arch Pharmacol 369(3):281–6.
Canavan D, Yarnell E (2005) "Successful treatment of poison oak dermatitis treated with Grindelia spp (gumweed)" J Altern Complement Med 11(4):709–10.
Ellingwood F (1919) American Materia Medica, Pharmacognosy and Therapeutics 11th ed (Sandy, OR: Eclectic Medical Publications, reprinted 1998), available free online at Michael Moore's website, www.swsbm.com.
Felter HW (1922) Eclectic Materia Medica, Pharmacology and Therapeutics (Sandy, OR: Eclectic Medical Publications, reprinted 1998), available free online at Michael Moore's website, www.swsbm.com.
Gladman AC (2006) "Toxicodendron dermatitis: Poison ivy, oak, and sumac" Wilderness Environ Med 17(2):120–8.
Gross ER (1958) "An oral antigen preparation in the prevention of poison ivy dermatitis; results in 455 cases of ivy sensitivity" Ind Med Surg 27(3):142–4.
Gauruder-Burmester A, Heim S, Patz B, Seibt S (2019) "Cucurbita pepo-Rhus aromatica-Humulus lupulus combination reduces overactive bladder symptoms in women---a noninterventional study" Planta Med 85(13):1044–53.
Kim BJ, Kim JH, Kim HP, Heo MY (1997) "Biological screening of 100 plant extracts for cosmetic use (II): Anti-oxidative activity and free radical scavenging activity" Int J Cosmet Sci 19(6):299–307.
McCutcheon AR, Ellis SM, Hancock RE, Towers GH (1992) "Antibiotic screening of medicinal plants of the British Columbian native peoples" J Ethnopharmacol 37(3):213–23.
McCutcheon AR, Ellis SM, Hancock RE, Towers GH (1994) "Antifungal screening of medicinal plants of British Columbian native peoples" J Ethnopharmacol 44(3):157–69.
Motz VA, Bowers CP, Kneubehl AR, et al. (2015) "Efficacy of the saponin component of Impatiens capensis Meerb in preventing urushiol-induced contact dermatitis" J Ethnopharmacol 162:163-7.
Oh SH, Haw CR, Lee MH (2003) "Clinical and immunologic features of systemic contact dermatitis from ingestion of Rhus (Toxicodendron)" Contact Dermatitis 48(5):251–4.
Reichling J, Neuner A, Sharaf M, et al. (2009) "Antiviral activity of Rhus aromatica (fragrant sumac) extract against two types of herpes simplex viruses in cell culture" Pharmazie 64(8):538–41.
Saxena G, McCutcheon AR, Farmer S, et al. (1994) "Antimicrobial constituents of Rhus glabra" J Ethnopharmacol 42(2):95–9.
Stein MF, Parsons E (2003) "Effectiveness in oral rhus toxicodendron solution for poison ivy" Int J Pharm Compd 7(4):272–5.
Differentiation of Species
"Leaves of three, leave it be."
Toxicodendron radicans
True poison ivy
Found in SE and south-central US, central Mexico.
Woody vine with aerial roots. Three leaflets with central leaf having longest petiole. Hairless leaves, petioles, and fruits.
Toxicodendron diversilobum
Pacific poison oak
Found in western US, BC, Baja California.
Grows in moist soils. Grows as shrub, easily mistaken for young oak tree. Leaves, petioles and fruits hairy.
Toxicodendron toxicarium
Eastern poison oak
Found in eastern US and Canada.
Grows in sandy soils. Grows as shrub. Leaves, petioles, fruits hairy.
Toxicodendron vernix
Poison sumach
Found in eastern US and Canada.
Grows in bogs and swamps as large shrub or small tree. Lacks triple leaflet configuration; entire margins. Fruit never red.
Rhus spp
Sumach
Widespread
Grow in wide range of habitats. Tend to be vines or shrubs. Short or absent petioles. Fruit always terminal (never occurs in Toxicodendron) and always red or purple.
Rhus aromatica (fragrant sumach): trifoliate leaves smell of citrus when crushes (poison ivy/oak odorless), all of N America except penisular FL
Rhus integrifolia (lemonade berry): simple, entire leaves (not trifoliate), coastal CA and Baja California
Rhus microphylla (littleleaf sumac): Mexico, TX, NM, Madrean Sky Islands in southern AZ
Rhus ovata (sugar sumac): simple leaf, CA, AZ, Baja California
Rhus trilobata (skunkbush sumac): trifoliate, widespread in western N America and Mexico
True poison ivy
Found in SE and south-central US, central Mexico.
Woody vine with aerial roots. Three leaflets with central leaf having longest petiole. Hairless leaves, petioles, and fruits.
Toxicodendron diversilobum
Pacific poison oak
Found in western US, BC, Baja California.
Grows in moist soils. Grows as shrub, easily mistaken for young oak tree. Leaves, petioles and fruits hairy.
Toxicodendron toxicarium
Eastern poison oak
Found in eastern US and Canada.
Grows in sandy soils. Grows as shrub. Leaves, petioles, fruits hairy.
Toxicodendron vernix
Poison sumach
Found in eastern US and Canada.
Grows in bogs and swamps as large shrub or small tree. Lacks triple leaflet configuration; entire margins. Fruit never red.
Rhus spp
Sumach
Widespread
Grow in wide range of habitats. Tend to be vines or shrubs. Short or absent petioles. Fruit always terminal (never occurs in Toxicodendron) and always red or purple.
Rhus aromatica (fragrant sumach): trifoliate leaves smell of citrus when crushes (poison ivy/oak odorless), all of N America except penisular FL
Rhus integrifolia (lemonade berry): simple, entire leaves (not trifoliate), coastal CA and Baja California
Rhus microphylla (littleleaf sumac): Mexico, TX, NM, Madrean Sky Islands in southern AZ
Rhus ovata (sugar sumac): simple leaf, CA, AZ, Baja California
Rhus trilobata (skunkbush sumac): trifoliate, widespread in western N America and Mexico