In three different experimental series with 22 experimental and 21 control cats it is demonstrated that DH-ergotoxine mesylate (Hydergine®) improves EEG energy, disturbed by temporary ischemia, in the isolated perfused cat head. It could be shown that improvement of EEG energy and lowering of arteriovenous lactate difference can be directly correlated. DH-ergonine improves experimentally induced metabolic decline as does DH-ergotoxine, but at one tenth of the dosage.