The action of lipids on haemostasis has already been shown. The authors study possible changes of haemostasis induced by the use of a substance: Trive 1000 containing 3.8 g of Soya oil and 0.3 g of Soya lecithin per 100 ml. Twenty patient received 1 litre per day over a period of ten days and were compared with 16 controls receiving glucose and amino acides without lipids. Studies of haemostasis included: overall coagulation by the thrombo-elastogram, P.R.P. (platelet rich plasma), estimation of the co-factors of the prothrombin complex, thrombin and reptilase times, platelet count, platelet stickiness using the method of HELLEM, platelet aggregation using the method of Born, plasminogen and plasmin activity by the pH STAT method, and P.D.F. levels. These examinations were carried out on the 1st, 3rd, 5th, 7th and 9th postoperative days. The results in the patients receiving Trive 1000 were as follows: no change in blood coagulation, progressive fall in platelet activity in the sense of hypoaggregability which was significant from the 5th day onwards only. There was no change in fibrinolysis. By contrast, there was anaemia, as determined on the basis of a fall in haematocrit, maximal on the 5th day and attributed by the authors to the haemolytic properties of triglycerides. In conclusion, Trive 1000 had no signifcant influence on haemostasis, apart from platelet hypoaggregability of moderate degree after prolonged treatment and perhaps haemolytic anaemia.