BACKGROUND: Various rat models have been used to study subarachnoid hemorrhage related to a stress ulcer. However, these models have many problems such as high mortality, low success rates, and a bias due to a long procedure time. The purpose of this study was to develope a more reliable rat model for the study of subarachnoid hemorrhage related to a stress ulcer. METHODS: Sprague-Dawley rats were anesthetized, and various volume of autologous blood were injected into the basal cistern by percutaneous injection. Mild stress consisting of restraint plus 4degreesC cold water immersion, 20degreesC cold water immersion, or 4degreesC cold water immersion with 40degreesC water rewarming were used to produce a stress ulcer. Thirty minutes after water immersion, rats were euthenized and the relative ulcer length (RUL) was measured. RESULTS: Experimental subarachnoid hemorrhage by an injection of 0.2 ml autologous blood and three cycles of restraint plus 4degreesC cold water immersion with 40degreesC water rewarming produced a marked ulceration without mortality and a significant neurologic deficit. CONCLUSIONS: An injection of 0.2 ml autologous blood combined with three cycle of restraint plus 4degreesC cold water immersion with 40degreesC water rewarming is an ideal model to study subarachnoid hemorrhage related to a stress ulcer.