Organic volatiles emitted by a grass Miscanthus sinensis were collected using a Tedlar film bag and Tenax GC adsorbent. Analyses were performed on a gas chromatograph and a GC/MS system. The result indicates that this plant emits cis-3-hexen-1-o1 (leaf alcohol) as a major volatile component. The emission rate of this alcohol determined in May and September showed a marked diurnal variation, increasing in the morning with a maximum at noontime followed by a rapid decrease. This alcohol was also emitted by certain herbaceous and woody plants.