Pyrethrum is the dried flower heads of Chrysanthemum cinerariaefolium, an annual herb native to the Balkans but now widely cultivated globally including Kenya, Japan, Yugoslavia, and India. Pyrethrum flowers contain 1-2% pyrethrins, a group of esters that are insecticidal. Specifically, pyrethrins I and II consist of esters from pyrethrolones/cinerolones and chrysanthemic/pyrethric acid. Pyrethrum is used as an insecticide due to its strong contact poisoning of insects.

1. Pyrethrum
Synonyms: Insect flower, Pyrethri Flores, Flores Insectarium
Botanical source: Pyrethrum Flower consists of the dried flower-heads
of Chrysanthemum cinerariaefolium Vis., an annual herb of the family
Compositae.
Geographical source: The Pyrethrum flower plant is indigenous to the
Balkans. The plant is widely cultivated throughout the world, the
principal sources being Kenya, Japan, Yugoslavia, East Central Africa,
Brazil, and India.
Organoleptic Evaluation-
1- Colour- Cream to straw
2- Odour- Characteristic and aromatic.
3- Taste- Bitter Followed by numbers.
4- Size- 10-15mm in diameter.

2. Chemical Constituents of Pyrethrum
The insecticidal properties of Pyrethrum flowers are due to two groups
of esters, known as Pyrethrins I and Pyrethrins II, present in them (1.0 to
2.0 percent). These are esters of several keto alcohols (pyrethrolones and
cinerolones) and chrysanthemic acid (giving pyrethrins I) or pyrethric
acid (giving pyrethrins II). These are collectively termed as “the
pyrethrins”. Official pyrethrum flowers should not contain less than 1.3
percent of total pyrethrins.
Uses: Finely powdered Pyrethrum Flower is used as an insecticide. It is
a strong contact poison for insects.