Cymiazole is an antiparasitic active ingredient used in veterinary medicine in livestock against some external parasites (lice, mites, ticks). It is not used against agricultural or household pests. It belongs to the chemical class of the amidines.

Common name: CYMIAZOLE

Type: pesticide
Chemical class: amidine (formamidine)


Molecular structure of CYMIAZOLE







Type of action: contact, non systemic ectoparasiticide: tickicide, acaricide, louisicide
Main veterinary parasites controlled: ticks, mites, lice

Efficacy against a specific parasite depends on the delivery form and on the dose administered. National regulatory authorities determine whether a product is approved for a given indication, i.e. use on a particular host at a specific dose and against a specific parasite. Check the labels of the products available in your country.

Click here for general information on features and characteristics of PARASITICIDES.


Oral LD50, rat, acute*:  725 mg/kg
Dermal LD50, rat, acute*: >3100 mg/kg
* These values refer to the active ingredient. Toxicity has to be determined for each formulation as well. Formulations are usually significantly less toxic than the active ingredients.

WARNING: cymiazole is toxic for horses!

MRL (maximum residue limit) set for animal tissues (either beef, mutton pork or chicken)*:

  • CODEX: No
  • EU: No
  • USA: No
  • AUS: No

* This information is an indicator of the acceptance of an active ingredient by the most influential regulatory bodies for use on livestock. MRL's for animal tissues may be set also for agricultural pesticides that are not approved for use on animals but are used on commodities fed to animals. A MRL may be also set in the form of an IMPORT TOLERANCE for active ingredients not approved in a particular country but approved for imported animal commodities.

Withholding periods for meat, milk, eggs, etc. depend on delivery form, dose and national regulations. Check the product label in your country.

General safety information for antiparasitics is available in specific articles in this site (click to visit):


Never use agricultural or hygiene products with this or any other active ingredient on livestock or pets, even if there are veterinary products with this same active ingredient approved for use on animals. The formulations for agricultural or hygiene use are different and may be toxic for livestock or pets.

It is obvious that veterinary products are not intended for and should never be used on humans!!!


Decade of introduction: 1970
Introduced by: CIBA-GEIGY → NOVARTIS
Some original brands: TIFATOL, EKTOBAN (mixed with cypermethrin), APITOL (bees)
Patent: Expired (particular formulations may be still patent-protected)

Use in LIVESTOCK: Yes, very scarce
Use in

Main delivery forms: 

Use in human medicine: No
Use in
public/domestic hygiene: No
Use in
agriculture: No
Generics available: 
Yes, very few


On livestock: Yes: not uncommon in cattle ticks (Boophilus spp), and increasing.

Visit also the section in this site about parasite resistance to antiparasitics and more specifically to amidines.


Cymiazole is the only veterinary amidine being marketed besides amitraz. It was moderately used in the 1980's in certain countries, alone or mixed with cypermethrin. Since then usage on livestock is very scarce. It is also used against Varroa mites in bees.

Cymiazole is a good tickicide. Its knockdown effect on cattle ticks is similar to the one of amitraz, but it has almost no residual effect. In contrast with amitraz, cymiazole is stable in the dip wash and doesn't need to be stabilized.

As amitraz, cymiazole does not control biting flies and other bloodsucking insects and is toxic for horses.

Mechanism of action of cymiazole

The acaricidal activity of cymiazole is similar to amitraz, i.e. it has an antagonistic effect on octopamine receptors of the nerve cells in the brain. Parasites become hyperexcited, paralyzed and eventually die. This mode of action is different from those of synthetic pyrethroidsorganophosphates and other ectoparasiticides. 

Click here to view the list of all technical summaries of antiparasitic active ingredients in this site.