Disclosed is a novel use of rice, rice bran or rice hull extract as a histamine receptor antagonist. The rice, rice bran or rice hull extract may be used as a natural antihistamine to prevent or treat allergic rhinitis, inflammatory bowel disease, asthma, bronchitis, nausea, gastric and duodenal ulcer, gastroesophageal reflux disease, sleep disorder, anxiety and depression. It provides comparable or better effect of decreasing sleep latency, increasing sleep duration and increasing non-REM sleep as compared to diazepam, which is currently used as sleeping drug. Derived from the natural product rice, rice bran or rice hull, it has no side effect such as cognitive impairment, resistance or dependency even after long-term use.
