Despite an increasing use of intravenous lipid emulsion in the treatment of the poisoned patient, the mechanism behind lipid rescue has not been elucidated. The most widely accepted hypothesis, the "lipid sink/sponge" model, suggests that intravenous lipid emulsion entraps xenobiotics intravascularly, thereby preventing them from reaching sites of toxicity. Additionally, intravenous lipid emulsion may redistribute xenobiotics to areas of higher lipid content. However, other mechanisms of actions of lipid emulsion, supported by observations from animal experiments, are vasoconstrictive and cardio-tonic effects. These effects could be secondary to direct activation of sodium, potassium or calcium channels in the myocardium, or alternatively fatty acid-induced modulation of the metabolic properties of mitochondria. Both mechanisms could result in hemodynamic stabilization. The potential beneficial effects of lipid emulsion on hemodynamic instability beyond the lipid sink have led to the notion that intravenous lipid emulsion could be valuable in the treatment of poisonings with non-lipophilic xenobiotics.