Secondary metabolites, which have an important role in regulating plants' relationship with the environment, are affected by soil pollution. Thus, it is important to describe the mechanism in which lemon balm's (Melissa officinalis L. subsp. officinalis) secondary metabolite accumulation is affected by Cadmium (Cd) stress. For this purpose, lemon balms seedlings that were grown in a controlled environment were exposed to increasing Cd stress and the relationship of lemon balm's growth and development with EO (essential oil) accumulation were investigated. Morphological, anatomical and physiological parameters of plants' that were exposed to Cd significantly decreased in parallel with increasing Cd concentration. Impairments in growth and development of lemon balm due to increasing Cd concentrations also affected EO accumulation. However, this destructive effect was most evident on EO accumulation amongst all investigated parameters. Furthermore, amount of EO decreased by 97%, at the highest concentration. In conclusion, Cd might have damaged both the EO producing mechanism and the structures that produce EO by inhibiting plant growth. Therefore it is important to reveal the responses of all parameters which affect EO production of medicinal plants under various stress conditions.