Posttraumatic spinal cord blood flow (SCBF) was assessed after elevating the mean systemic arterial pressure (mSAP) with a blood transfusion, or with an infusion of dopamine. The effect of the anesthetic agent, gamma hydroxybutyrate, was also assessed. Flows were measured using the 14C-antipyrine autoradiographic method. Animals were injured at T-1 by acute compression of the spinal cord with a clip exerting a pressure of 175 gm. Uninjured animals, with mSAP's of 120.0 +/- 17.0 mm Hg, had gray and white matter flows of 74.2 +/- 22.3 and 18.7 +/- 6.7 ml/100 gm/min, respectively, while injured untreated animals had mSAP's of 82.5 +/- 14.1 mm Hg and gray and white matter flows of 13.3 +/- 12.1 and 3.9 +/- 3.9 ml/100 gm/min, respectively, at the injury site. Blood transfusion raised the mSAP's to 127.5 +/- 13.7 mm Hg in the injured animals and doubled the flows in gray and white matter to 25.6 +/- 30.2 and 6.3 +/- 6.4 ml/100 gm/ml, respectively. Dopamine did not have as beneficial an effect as blood transfusion on either the mSAP (101.0 +/- 16.7 mm Hg) or the SCBF (gray and white matter flows of 18.4 +/- 12.4 and 5.8 +/- 5.9 ml/100 gm/min). Gamma hydroxybutyrate (GHB) had almost no effect on the mSAP or SCBF of normal animals, and in injured animals produced only a unilateral increase in flow on the less severely injured side, without affecting the mSAP.