Thromboxane-prostacyclin imbalance may be an important determinant of platelet-vessel wall interactions that are vital in circulatory homeostasis. In experimental spinal cord injury, the vascular damage contributes substantially to the process of progressive secondary injury culminating in post-traumatic myelopathy. In this study, we found a time-dependent alteration of thromboxane-prostacyclin balance in the injured spinal cord with thromboxane dominance during the first 2 h: a time when maximal vascular injury is reflected by extravasation of 125I-labelled serum albumin. The thromboxane-prostacyclin imbalance reverted to favor prostacyclin by 18 h post-injury. This time-dependent alteration of thromboxane-prostacyclin balance should be considered in the planning of therapeutic attempts to prevent secondary injury by pharmacological modulation of platelet-vessel wall interaction.