The effects of different HAc (acetic acid) etching procedures were investigated on T4 and extruded Mg-5Gd to achieve defined surfaces and a homogenous degradation behaviour. Samples were dipped into HAc solution with five different concentrations for three durations. In total fifteen different etching conditions were tested according to the degradation resistance in physiological solution. The cell culture medium consists of DMEM, Glutamax, 10 % FBS and 1 % Streptomycin/Penicilin solution. A screening test was performed to select the etching combinations with the lowest initial mean degradation depth. The promising etching procedures were chosen for further long term testing up to 30 days in cell culture medium. The surface of the etched samples and selected samples after degradation were characterized by interferometry, OM, SEM, XRD and µXRF to correlate the influence of morphology, roughness and microstructure on the degradation rate. It has been shown that etching with HAc solution decreases the degradation rate of Mg-5Gd. Especially one etching combination of 250 g/L and 150 s lead to a homogenous degradation with low initial degradation and degradation rate compared to non-etched Mg-5Gd.