Betel-quid is widely used around the world as a stimulant for the autonomic nervous system. The aim of this study was to assess the effect of betel-quid chewing on autonomic nervous modulation by using spectral heart rate variability (HRV) analysis. Twenty healthy young adults were included in this study. Each subject chewed a single betel-quid containing one betel nut or a piece of chewing-gum for 60 min on different days in random order. Spectral HRV measures were obtained before, and 5, 30 and 60 min after starting to chew betel-quid or gum. Sequential changes in HRV measures were compared between chewing gum and betel-quid. Heart rate was significantly elevated after 5 min chewing betel-quid, but not after chewing gum. The normalized low-frequency power and low-/high-frequency power ratio were elevated after 5 min chewing gum or betel-quid; however, the normalized high-frequency power was reduced after 5 min chewing gum or betel-quid. The percentage changes in total power after 5, 30 and 60 min chewing betel-quid were significantly lower than those after chewing gum. This study confirms that novice chewing of betel-quid modulates autonomic nervous system activity; transiently enhancing sympathetic activity and gradually suppressing vagal activity in healthy young adults.