PURPOSE: To obtain the subject readily handleable composition which is a freeze- dried substance containing a cyclodextrin clathrate compound of prostaglandin E1 and glucose as blending ingredients, excellent in stability at ambient temperature and having high safety.

CONSTITUTION: This composition is a freeze-dried substance containing a cyclodextrin clathrate compound of prostaglandin E1 and glucose as blending ingredients. The blending ratio of the glucose is 25-150 pts.wt., preferably 35-100 pts.wt. based on 1 pt.wt. prostaglandin E1.