The invention relates to membranes for haemodialysis, haemofiltration and/or plasmapheresis formed from substituted or unsubstituted cellulose carbamate having a carbamate nitrogen content in the range between 0.1 and 6%. The invention also relates to a method for manufacturing membranes of this type as well as to their use for blood detoxification within the framework of ultrafiltration, high flux dialysis, haemo-diafiltration and plasmapheresis of the blood.