The serotonin (5-hydroxytryptamine) type 3 receptor is an important target in the control of digestive dysfunction such as anorexia and bulimia, and 5-HT receptor antagonists are effective against eating disorder and the early-phase chemotherapy and radiotherapy evoked vomiting. Our previous research of revealed the presence of iridoids, which showed potent antitumor activities. Here, we explored the effects of 10π aromatic iridoid desacylbaldrinal isolated from on the 5-HT receptor current. We performed whole cell recordings of 5-HTA receptor currents in the presence of the compound. The result indicated that desacylbaldrinal inhibited the 5-HT-mediated 5-HTA receptor current.