To analyze age-dependent effects of a plasma donation on the regeneration of plasma proteins two groups of first time plasma donors were selected ( 50 years). By measurements of hematological and biochemical parameter, immunoglobulins, procoagulators and inhibitors of coagulation before and after a plasma donation the kinetic of regeneration until three weeks was followed up. It can be concluded that a single plasma donation affects the generation in younger and older donors in a different way. Procoagulators and inhibitors show the same behavior, except the donation related elevation of fibrinogen in young donors. Especially the retarded regeneration of cholinesterase and immunoglobulins in the male young group should be taken into consideration for frequent plasma donations and autologous preoperative plasma donations.