The research study in this chapter was aimed to determine and characterize the bioactive compounds present in three medicinal plants (Ageratum conyzoides, Chromolaena odorata, and Ficus exasperata) commonly used in Nigeria, especially in the southeast Geopolitical Zone for the management of ailments. The biological activities of these plants were established using phytochemical detection schemes of GC-MS and FT-IR. From the results obtained, the methanolic leaf extract of Chromolaena odorata recorded the highest bioactive compounds followed by those of Ageratum conyzoides and Ficus exasperata. These confirm the wide use of C. odorata in herbal medicine. The blend of the different leaf extracts may be of health benefits owing to the distribution of the compounds within each plant sample. However, it is recommended that a more thorough investigation should embark to quantitatively isolate, purify, package, and market-specific bioactive compounds.