The present invention provides a novel usage of a rice, rice bran, or chaff extract as a histamine receptor antagonist. The rice, rice bran, or chaff extract is used as a natural antihistamine agent for preventing or treating allergic rhinitis； inflammatory bowel disease； asthma； bronchitis； vomiting； gastric and duodenal ulcer； gastroesophegeal reflux； sleep disorders； anxiety； and depression, and shows similar or improved effectiveness in reducing the time required for entering a hypnagogic state and increasing sleeping time, compared to diazepam, which is an existing drug used as a sleep inducing agent. The rice, rice bran, or chaff extract is a natural product and does not have side effects such as cognitive impairment, resistance, or dependency even with long-term use.
