This paper aims at presenting the properties and actions of individual lipids, as determined via various animal experiments, on the organ systems of the area of the splanchnicus and the lung that are of particular relevance for the intensive-care physician, and to derive possible therapeutic options form these data. Although so far no data are available on newly introduced kinds of fat such as fish oil used in parenteral feeding of critically ill patients, it will be the aim of future therapeutic concepts to arrive at optimal combinations for the individual patient of the pharmacological, energetic and essential properties of the individual classes of fatty acids. Structured lipids may possibly be suitable for this task in an ideal manner, the glycerol molecule of which is esterified with linoleic acid as an essential constituent of food, a medium-chain fatty acid as energy carrier, and an omega-3 fatty acid as immunomodulator. The question as to whether such mixtures can eventually be administered in a not too distant future to parenterally fed patients after trauma and during septic condition for their benefit, can be answered only by means of clinical studies that will have to be conducted in years to come.