Lantana camara L. (Family Verbenaceae) is an ornamental herb found in tropical and sub-tropical countries. It has been widely used in traditional medicine for the treatment of various illnesses. L. camara contains a large number of phytochemical compounds. Polyphenol metabolites of L. camara L. are the major bioactive constituents. Recently scientifically proven therapeutic activities of L.camara include antibacterial, antioxidant, antipyretic, insecticidal, antimicrobial, wound healing, and anti-urolithiatic activities. Limited information is available regarding the phytoconstituents and other health value of Lantana flowers. The fragmentation behavior of phenolic acid derivatives and other acids was investigated using HPLC-PDA-ESI-MS in negative mode where even minor components were detected due to the high sensitivity of mass spectrometer detector. The given acids profile led to discovery of many unreported metabolites including hydrogen-bonded dimers of acids and acids bound to sugars. The anti-coagulant activity measured by estimation of prothrombin time (PT) using normal citrated human plasma and heparin as positive control revealed that Lantana flowers and roots extracts increased the clot time relative to the control. This activity may be attributed to the high-phenolic content of the flowers as many studies have reported.