The purpose of this study was to analyse the actual routines surrounding the use of peripheral cannulae and the occurrence of complications Thirty surgery patients and 30 internal medicine patients were observed daily at a medium-sized hospital The patients were followed from the time the cannula was inserted until after withdrawal and until both the insertion site and the vein were free from pain The results showed that most of the cannulae were placed on the upper side of the hand and sizes most frequently used were 1-0 and 1-2 mm The fixation was unsatisfactory in 23 cases already after the second day Twenty-three cannulae were removed after 24 hours Thirty-seven (62%) patients were stated to have thrombophlebitis phlebitis in different degrees Only seven cannulae fulfilled the criteria for good cannula care and handling The frequency of complication was especially high when fructose-glucose, antibiotics or anticoagulants were given There was no documentation in the patient record, according to current laws in Sweden The complications observed were redness, swelling, haematoma, subcutaneous swelling and suppurating infection The study showed that the longer the cannula had been in situ, the greater were the complications (very distinct after 24 hours) The care and handling was unsatisfactory to very unsatisfactory in 52% of the cases Complications can last for a very long time In this research, pain was noted up to 5 months after the cannulae were removed