Objectives : Zizyphus seed has long been used in hypnotics and sedatives in oriental medicine, and it is reported that the Zizyphus seed elicited a variety of pharmacological actions besides CNS depression. We did a clinical study on the effectiveness of Zizyphus seed (Ansim-san) for insomnia in stroke patients. Methods : To 41 stroke patients suffering from insomnia, we administered the extract of Zizyphus seed (Ansim-san). Outcome measures were subjective in nature and included a morning questionnaire, visual analog scales, and observation forms by study personnel. We also, to find the applicable symptom-complex of Zizyphus seed (Ansim-san), examined accompanying symptoms. Results : 1. Zizyphus seed extract use meant that sleep latency was shorter, total sleep time was longer, number of wakenings was lower, wake time during sleep was shorter, sleep quality was improved, condition upon awakening was improved, ability to concentrate was improved, and the patients fell asleep more easily (P<0.001). There were no differences in morning sleepiness. 2. Among accompanying symptoms, an oppressed feeling in the chest was significant (P=0.035) in the patients who improved sleep quality. Conclusions : The results of this clinical study suggest that in stroke patients, Zizyphus seed (Ansim-san) can be effective for insomnia, and significantly effective in patients who have an oppressed feeling in the chest.