Parishin C, a major component of Gastrodia elata BLUME (GE), was purified from GE. Because GE modulates the serotonergic system and the 5-HT1A receptor is an important therapeutic target of schizophrenia, we examined whether parishin C affects phencyclidine-induced abnormal behaviors in mice. Phencyclidine-induced abnormal behaviors were significantly ameliorated by parishin C. These effects were reversed by WAY 100635, a 5HT1A–receptor antagonist. Consistently, parishin C showed high affinity at 5-HT1A receptor as well as a 5-HT1A–agonist activity in a 8-OH-DPAT–stimulated [35S]GTP-γS binding assay. Our results suggest that the antipsychotic effects of parishin C require activation of 5-HT1A receptors.