This study investigates the role of jasmonic acid and its methyl ester in the elicitation of secondary metabolite production in plant cell cultures. The authors found that exposure of cell suspension cultures of *Rauwolfia canescens* and *Eschscholtzia californica* to a yeast elicitor leads to a rapid and transient accumulation of endogenous jasmonic acid and methyl jasmonate. Exogenously supplied methyl jasmonate also induced the accumulation of secondary metabolites in 36 plant species tested, including benzo[c]phenanthridine alkaloids in *E. californica*. The addition of methyl jasmonate initiated de novo transcription of genes involved in the chemical defense mechanisms of plants, such as phenylalanine ammonia lyase (PAL). These findings demonstrate the integral role of jasmonic acid and its derivatives in the intracellular signal cascade that triggers the accumulation of secondary compounds in plant cell cultures.This study investigates the role of jasmonic acid and its methyl ester in the elicitation of secondary metabolite production in plant cell cultures. The authors found that exposure of cell suspension cultures of *Rauwolfia canescens* and *Eschscholtzia californica* to a yeast elicitor leads to a rapid and transient accumulation of endogenous jasmonic acid and methyl jasmonate. Exogenously supplied methyl jasmonate also induced the accumulation of secondary metabolites in 36 plant species tested, including benzo[c]phenanthridine alkaloids in *E. californica*. The addition of methyl jasmonate initiated de novo transcription of genes involved in the chemical defense mechanisms of plants, such as phenylalanine ammonia lyase (PAL). These findings demonstrate the integral role of jasmonic acid and its derivatives in the intracellular signal cascade that triggers the accumulation of secondary compounds in plant cell cultures.