Psidium guajava) is a compact tropical tree or shrub belonging to the Myrtaceae family. Originally native to tropical America, The literature survey has unveiled the diverse medicinal properties of guava, which have been documented worldwide through ethnobotanical and ethnopharmacological surveys so it is newly cultivated in Iraq, this research is considered the first of its kind to extract essential oil from guava leaves and fatty acid from petroleum ether fraction of guava leaves newly cultivated in Iraq to identify the compounds present and test the cytotoxic activity of petroleum ether fraction on HEPG2 cell line. The extraction of essential oil (EO) from (Guava) leaves was carried out using the hydro distillation method with the Clevenger(apparatus and the (EO) was subjected to GC/MS and around 40 compounds were identified, some of them only identified in Iraqi guava essential oil leaves. Ultrasonic-assisted extraction (UAE)was used for the extraction guava leaves and the crude extract after drying suspended with water for fractionation method (3 times) with 100 ml of different solvents polarity in ascending manner(petroleum ether, chloroform, ethyl acetate, and n. butanol) petroleum ether fraction was dried and subjected to GC mass spectrometry many compounds identified in petroleum ether fraction and large amount of gamma-sitosterol was found in the petroleum ether fraction of Iraqi guava leaves compared to its amount in the rest of the guava leaves in the world.