The objective of this study was to investigate the effects of the elicitors, salicylic acid (SA) and chitosan, on the improvement of Stemona alkaloid production in hydroponic cultures of S. curtisii. In vitro plantlets were used as plant materials. The elicitors were added into the culture medium and samples of the roots and medium were collected on week 2 and 4 after the elicitor addition and then analyzed for Stemona alkaloid production by high performance liquid chromatography (HPLC). This study revealed that both SA and chitosan increased production of three Stemona alkaloids and that chitosan is better than SA for the enhancement of the production of these alkaloids. The elicitation by 20 mg L-1 of chitosan for 4 weeks induced highest amount of oxyprotostemonine (274.31 ¿g g-1 DW) stemocurtisine (35.46 ¿g g-1 DW) and stemocurtisinol (99.48¿g g-1 DW), which were 1.9, 2.0 and 1.5 fold higher than that of the control, respectively.