Pyrethrum
Scientific names: Tanacetum cinerariifolium, Chrysanthemum cinerariifolium, Pyrethrum cinerariifolium
Family: Asteraceae/Compositae
Alternate names: Chrysanthème Insecticide, Dalmation Insect Flowers, Dalmation Pellitory, Pelitre, Piretro, Pyrèthre, Pyrèthre de Dalmatie
Background
Pyrethrum is a plant (Chrysanthemum cinerariifolium). Pyrethrum is also the name of the crude extract obtained from flowers of this plant.
Be careful not to confuse pyrethrum with pyrethrin. Pyrethrin refers to a more refined extract of pyrethrum. Pyrethrin is in body lice medicines such as A-200 Pyrinate, Barc, Lice-Enz, Licetrol, Pronto, R and C, RID, Tisit, Tisit Blue, and Triple X.
People apply pyrethrum directly to the skin as an insecticide, particularly for head lice, crab lice and their nits, and mites (scabies).
Be careful not to confuse pyrethrum with pyrethrin. Pyrethrin refers to a more refined extract of pyrethrum. Pyrethrin is in body lice medicines such as A-200 Pyrinate, Barc, Lice-Enz, Licetrol, Pronto, R and C, RID, Tisit, Tisit Blue, and Triple X.
People apply pyrethrum directly to the skin as an insecticide, particularly for head lice, crab lice and their nits, and mites (scabies).
Safety Safety definitions
The commercially available combination of pyrethrins (0.17-0.33%) and piperonyl butoxide (2-4%) seems to be safe when applied to the skin in a nonaerosol product.
Pyrethrum is POSSIBLY SAFE when used on the skin in amounts less than 2 grams. While pyrethrum has limited toxicity at low doses, it can cause some side effects such as headache, ringing of the ears, nausea, tingling of fingers and toes, breathing problems, and other nervous system problems.
Children: It’s UNSAFE to put pyrethrum on children less than two years old.
Asthma: Exposure to pyrethrin might make asthma worse. Avoid using pyrethrum or pyrethrin products if you have asthma.
Allergy to ragweed and related plants: The pyrethrum flower or pyrethrin extracted from it may cause an allergic reaction in people who are sensitive to the Asteraceae/Compositae family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many others. If you have allergies, be sure to check with your healthcare provider before using pyrethrum.
Pyrethrum is POSSIBLY SAFE when used on the skin in amounts less than 2 grams. While pyrethrum has limited toxicity at low doses, it can cause some side effects such as headache, ringing of the ears, nausea, tingling of fingers and toes, breathing problems, and other nervous system problems.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Not enough is known about the use of pyrethrum during pregnancy and breast-feeding. Stay on the safe side and avoid use.Children: It’s UNSAFE to put pyrethrum on children less than two years old.
Asthma: Exposure to pyrethrin might make asthma worse. Avoid using pyrethrum or pyrethrin products if you have asthma.
Allergy to ragweed and related plants: The pyrethrum flower or pyrethrin extracted from it may cause an allergic reaction in people who are sensitive to the Asteraceae/Compositae family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many others. If you have allergies, be sure to check with your healthcare provider before using pyrethrum.
Effectiveness
NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Effective Effectiveness definitions
- Head lice and crab lice. Applying pyrethrins to the skin in concentrations of 0.17% to 0.33% for 12-24 hours is effective for treating head lice and crab lice. Pyrethrins are usually combined with piperonyl butoxide (2% to 4%) to increase effectiveness.
Inffective Effectiveness definitions
- Scabies (mites).
Dosing & administration
The following doses have been studied in scientific research:
APPLIED TO THE SKIN:
APPLIED TO THE SKIN:
- For treating head lice and crab lice: An over-the-counter (OTC) product that combines pyrethrins (0.17% to 0.33%) and piperonyl butoxide (2% to 4%) is applied to the affected area and allowed to remain for at least 10 minutes. The product is then thoroughly washed off with warm water. Pyrethrins are extracted from pyrethrum, and kill lice by harming their nervous systems.
Interactions with pharmaceuticals
It is not known if Pyrethrum interacts with any medicines. Before taking Pyrethrum, talk with your healthcare professional if you take any medications.
Interactions with herbs & supplements
There are no known interactions with herbs and supplements.
Interactions with foods
There are no known interactions with foods.
Action
The active chemicals, the pyrethrins, are toxic to insect nervous systems.
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This monograph was last reviewed on 26/08/2023 10:00:00 and last updated on 24/12/2012 22:18:27. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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Natural Medicines rates safety based on scientific evidence according to the following scale: Likely Safe, Possibly Safe, Possibly Unsafe, Likely Unsafe, Unsafe, and Insufficient Evidence to Rate. For more information about Natural Medicines’ Safety Rating System, click here.
The Natural Medicines Effectiveness Ratings are assigned for specific indications. A product might be rated "Possibly Effective" for one condition, but be rated "Likely Ineffective" for another condition, depending on the evidence. For more info click here.
