Objective: The anti-malarial drug, artemisinin, is harvested from the leaves of adult Artemisia annua L. plants. As its concentration in juvenile plants is very low, the present study aimed to assess if the airborne signaling molecule, β-ocimene, could be used to enhance artemisinin accumulation in juvenile A. annua plants. Results: Application of exogenous β-ocimene increased artemisinin accumulation in A. annua. Treatment with 10 µM β-ocimene for 4 days resulted in juvenile plants accumulating artemisinin contents of up to 25 mg/g (2.5%) ...