Carbonic anhydrase (CA) is an enzyme which plays a role in various homeostatic mechanisms, such as acid-base balance and electrolyte secretion in a various tissues. This study was aimed at determining and comparing possible alterations in activity of this enzyme caused by the use of old (Carbamazepine, Phenytoin Sodium, Sodium Valproate) and new (Levetiracetam, Pregabalin, Gabapentin, Oxcarbazepine) anti-epileptic drugs. Blood samples were collected from the volunteers. The blood samples were centrifuged to separate plasma and erythrocyte package. Hemolysate was prepared from the red cells. CA I and II were purified from human erythrocytes by a simple one step procedure using Sepharose 4B-L-tyrosine-sulfonamide affinity column. CA I and II isozymes were treated with some anti-epileptic drugs, then the inhibition or activation of enzyme determined. The results of this study show that Levetiracetam is the most effective inhibitor for human erythrocytes carbonic anhydrase compared with the other anti-epileptic drugs.