The effect of an omental lipid fraction on the rate of skin flap survival in the back of the rat was assessed by planimetric and histological examination. Compared with the control group, those rats treated with the omental lipid fraction showed significant improvement of the flap survival area. On histological examination, the flap instilled with the omental lipid fraction showed vasodilatation and neovascularization between the flap and the bed. A topical application of the omental lipid fraction enhanced the skin flap survival area, and showed vasodilatation in the flap and neovascularization between the skin flap and the recipient bed.