There are numerous medicinal plants in the Southern and Eastern Nigeria. These plants are widely utilized in Nigerian traditional system of medicine for the treatment of countless of illnesses. This paper focused on the phytochemical and essential composition of the aerial parts of Leonurus cardiaca. The phytochemical and essential oil screening and characterization were carried out using high performance liquid chromatography and gas chromatography. Results obtained from this investigation showed seven different terpenoids and their total concentrations were 26.19 x 10-1 (mg/100 g), nine different phenolic acids (506.33 mg/100 g), twelve different saponin (62.33 mg/100 g), seven different cyanogenic glycosides (118.03 mg/100 g), thirteen different glycosides (16.17 mg/100 g), five (5) different anthocyanins (56.53 mg/100 g), twenty six different alkaloids (1.31 mg/100 g), six different flavonoids (7.31 mg/100 g), seven different sterol (5.91 mg/100 g), tannins (426.49 mg/100 g), and phytate (69.12 mg/100 g). Analysis for essential oils showed fourty one different essential oils (100. 00 %). Our uncovering indicated Leonurus cardiaca is an excellent source of terpenoids, saponins, alkaloids, anthraquinones, anthocyanins, phenolic acid, sterols, cyanogenic glycoside, phytate, tannins, glycosides, flavonoids and essential oils. This present research exemplify the preparatory detection for discretion or selection of Leonurus cardiaca potential source of novel therapies for the treatment of various diseases.