The Caribbean shrub, Clinopodium vimineum, had its essential oil (EO) and hydroalcoholic extracts analyzed across three growth stages: vegetative, flowering, and post-flowering. The chemical composition of the EOs was analyzed by GC/MS/FID and that of the extracts was studied by UHPLC/ESI-Q-Orbitrap-MS. Twenty six compounds (>0.1%) were detected in the EOs of C. vimineum. p-Menth-3-en-8-ol (35â40%) and pulegone (27â30%) were the major components. Among the hydroalcoholic extracts, hydroxycinnamic acids (18â46 mg/g) and glycosylated flavones (17â19 mg/g) were found. The amounts of rosmarinic acid (20â40 mg/g) in the extracts isolated from the hydrodistillation residual biomass were twice as high as those in the extracts from the fresh plant material. The antioxidant activity of the EOs and extracts was evaluated by the ABTS+â¢ and ORAC assays. No significant differences (p > 0.05) were found in the chemical composition or antioxidant activity of EOs and hydroalcoholic extracts, obtained from plants collected at different phenological stages.