The idea of autologous fat microtransplants has recently resurfaced because of interest by the press. Past experiments have shown that small amounts of fat may be transplanted with an expected survival rate between 10 and 50 percent without ectodermis. A great fund of knowledge exists showing that skin grafts will survive quite dependably if their thickness is up to about 0.0020 inch. For the first week or so, they live by diffusion and inosculation, and then neovascularization enables them to continue viability. I have developed a technique whereby fat is harvested through a blunt cannula with minimal vacuum to prevent explosion of the cellular fat globules. Fibrin and cellular debris are removed, and the fat globules are separated from the free fat, blood, and other constituents of the aspirate. Individual, free-floating 1- to 3-mm adipose fragments are then suspended in nutrient solution and injected through an 18-gauge needle. Multiple radial pathways, with each fat segment being separated from the other by host tissue, maximizes the host-prosthesis interface and the possibility for exchange of nutrients. I have attempted this procedure in more than 100 patients with widely varying results. In acne pits of the face, no significant improvement could be noted 6 weeks after injection. For the first few weeks, a near-perfect result was obtained, but none of these transplants in scarred areas of this kind have been of benefit. Injection of 10 to 50 cc in other areas has resulted in some cells (perhaps 10 percent) surviving over 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)