Abstract: Background and Objectives: Maturity of a plant is preceded by complex reactions, which leads to the production of a wide range of bioactive compounds with different therapeutic properties and possible toxicity. This study evaluated the antibacterial activities and toxicity of C. argentea at three growth stages; pre-flowering, flowering and post-flowering of two trials. Materials and Methods: Agar dilution technique was used for evaluation of antimicrobial action of C. argentea against three Gram-negative, three Gram-positive pathogenic bacteria and four fungi; while ciprofloxacin and nystatin were used as standards, respectively. The preliminary toxicity assessment was evaluated using Brine Shrimp Lethality Assay (BSLA), with amoxicillin and sea water as the negative and positive controls, respectively. Results: Acetone extracts were unable to inhibit the growth of all the organisms tested in all growth stages and at both trials. Streptococcus pyrogenes and P. aeruginosa were susceptible to the methanol extracts of all the growing phases of both trials at 10 mg mL–1, while Klebsiella pneumoniae was susceptible at 10 mg mL–1 to only the methanol post-flowering extracts of both trials. Moderate to high antifungal activity of the crude extracts of C. argentea were recorded on all the tested fungal strains. Candida albicans and P. aurantiogriseum were highly susceptible to the extracts with MIC value ranging from ≤0.625-5 mg mL–1 in both trials. The LC50 (>1 mg mL–1) values for C. argentea extracts recorded for all the growth stages of Artemia salina indicated that the plant extracts were non-toxic. Conclusion: These findings indicated that maturity stage influence antimicrobial activity of C. argentea. The best time to harvest for antibacterial properties would be the post-flowering stage and the pre-flowering stage for antifungal. Toxicity evaluation showed that C. argentea is not toxic at any stage of maturity.