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Secondary metabolites have great pharmaceutical value in medicine. This study evaluates the effect of alti-tude on the amount and variety of secondary metabolites in lavender plant from two sites located in Mazandaran prov-ince. Sampling was performed in a randomized design with three replications. After the plants were dried, essential oil was extracted by distillation. Isolation and identification of constituents of the oil were performed by gas chromato-graphy and gas chromatography connected to mass spectroscopy. The results of this research led to the identification of 22 (99.96% of the total constituents) and 24 (97.01% of the total constituents) constituents in Baladeh and Behshahr sa-mples, respectively. Characteristics constituents included Andoyorneol (22.36%), 1, 8 cineole (20.7%), camphor (8.69%), α-Cadinol (7.60%), Caryophyllene oxide (5.09%) and Propanol (18.4%) in Behshahr population samples and Borneol (26.78%), 1, 8 cineole (20.19%), camphor (9.59%), α-Cadinol (5.80%), caryophyllene oxide (4.99%) and pr-opanol (3.41%) in Baladeh population samples. The differences in the output and combination of the essential oils in-dicated that the environmental as well as genetic factors can affect the production and amounts of the chemical comp-ounds in medical plants. Therefore, medicinal plants should be cultured in proper areas based on the aim of cultivation and the desired type of active materials.