This article is dedicated to the research of the chemical compounds of aerial parts (stems and leaves) of Lactuca serriola L. The phytochemical investigation of the aerial parts of the L. serriola L. (320 g) revealed the presence of flavonoid derivatives. In the acetonic extraction of raw plant material the total extractive contents is researched by the Liquid chromatography–mass spectrometric (LC-MS) method and flavonoid derivatives have been identified. Totally 20 compunds obtained, 11 were identified and they were found belong to the carboxylic acid, monosaccharide, phenolic compounds and flavonoids. LC-MS experiments were realised by a Shimadzu 20 A HPLC system and identification of the substances were performed by Analyst 1.6 software. Gluconic acid, glucose, quercetin are amongst those which were identified. Gluconic acid itself is used in pharmaceutical industry and recognized safe to be used as a food additive by FDA and EU. L. serriola has been used in traditional folkloric medicine for the treatment of gastrointestinal, respiratory and numerous other diseases. It also has a high antioxidant capacity, sedative, hypnotic, diuretic, antioxidant, anesthetic, antispasmodic, anticancer, antibacterial, bronchodilator, vasorelaxant activities. Having availability, affordability, and medicinal importance draws the attention for investigation of various bioactive substances.