It is reported on the infusion, stimulation and microcatheter technique in an internal intensive therapy ward. From July 1st 1970 to November 11th 1974 were altogether laid 1,642 superior cavacatheters, 1,057 times by puncture of the subclavian vein and 585 times through the brachial veins. Compared with the usual infusion techniques the advantages of the cava-catheter technique consist in the fact that a constant venous approach is existing and that solutions of a high percentage and medicaments may be infused relatively undangerously. Apart from this the cava-catheter gives the possibility to carry out continuous measurements of the central venous pressure and guarantees the taking of blood samples at any time. The phlebitides or thromboses, respectively, which are regularly appearing in flexules lying longer than 40 hours are avoided in most cases. Taking into consideration the contraindications and the exact performance of the various methods especially early complications such as puncture of the arteries, pneumothorax, detachment of the catheter, extended haematomas and wrong positions of the catheter may be reduced to a minimum. As late complications distinct infections in the place of puncture, unclear, partly septic temperatures and clinically manifest thromboses were observed. In these cases the cava-catheters should be removed. The temporary electrostimulation through electrode catheters plays an important part in the emergency medicine and the mastering of the various methods of the cava-catherization is taken for granted. During the period of report altogether 423 stimulation catheters were laid. The cardiac microcatheterization should be reserved for more special cases.