Carbamazepine (CBZ) could be dissolved in Glycofurol (polyethylene glycol monotetra-hydrofurfuryl ether) with concentrations up to 100 mg/ml, and the solutions were stable for at least 14 days. Ethanol or benzyl alcohol was added without loss in solubility, while water, human serum albumin or Intralipid always led to immediate precipitation. The effect of a CBZ/Glycofurol solution on focal seizure threshold in the visual cortex in cats was investigated using a cerveau isolé preparation. Fourteen experiments were performed using i.v. injections of CBZ with concentrations ranging from 0.2 to 20 mg/kg. In all experiments with doses greater than 1 mg/kg the CBZ/Glycofurol injections exerted a pronounced and immediate effect on the seizure threshold, while Glycofurol alone was ineffective. On average, seizure threshold increased more than 5-fold with doses in the range of 5-20 mg/kg. Investigating the effect of CBZ/Glycofurol on picrotoxin-induced seizure activity in cats, 2 injections of 5 mg/ml of CBZ immediately stopped the seizure activity as evaluated by electrocorticography, while interictal activity remained.