Lipid granuloma of the peritoneum is an inflammatory reaction to the presence of exogenous oil within the peritoneal cavity. Synonyms include lipogranuloma, oil granuloma, oleoma, oleogranuloma, eleoma, tumors of chemical origin, or, depending upon the lipid used, paraffinoma, vaselinoma, and Lipiodol pelvic cyst. Despite the fact that intraperitoneal lipid granulomatosis may be easily diagnosed from its roentgenographic appearance, the condition has not been reported in the recent American radiological literature. The oil causing intraperitoneal lipid granulomatosis reaches the peritoneal cavity in any of four ways: by means of instillation by the surgeon as in the case of mineral oil or vaseline in the ill-advised attempt to prevent adhesions; via the uterine canal and fallopian tubes as in the use of Lipiodol for hysterosalpingography; via the same route where in the past mineral oil has been used as an abortifacient; and, at least theoretically, via the rectum in cases of perforation of the colon during the course of a mineral oil enema. As early as 1888, Martin, in Germany, moistened his sponges in olive oil and rubbed them lightly over the peritoneum in certain cases just before closing the abdominal incision. It appears that Blake in 1908 (2) was the first American to advocate the use of sterile oil to prevent intraperitoneal adhesions. He also apparently used sterile olive oil, but in the three decades to follow, mineral oil, vaseline, animal fat, and paraffin were used similarly. Norris and Davison in 1934 (11) apparently were among the first to call attention to the peritoneal reaction to liquid petroleum and to indicate that instead of preventing adhesions by its “lubricating” effect this practice results in the opposite effect. Mineral oil and vaseline almost uniformly result in a granulomatous reaction; vegetable oils will cause reactions, but less consistently (16, 17). The oil acts as a foreign body causing an inflammatory reaction which results in formation of granulomata and of dense adhesions between the viscera, mesentery, omentum, and the peritoneum. Encapsulation of the oil droplets produces cystic nodules surrounded by fibrous tissue containing foreign body giant cells. Calcification may then occur within the fibrous stroma and also in the periphery of the nodule. The granulomatous reaction appeared as soon as four months after the instillation of the mineral oil in one of the cases reported by Norris and Davison; in other cases up to thirty years elapsed before roentgenographically visible calcifications were discerned. In the early part of this century Lipiodol, a chemical combination of 40 per cent iodine bound to poppy-seed oil, was used both as a diagnostic agent for hysterosalpingography and also therapeutically as an “antiseptic” in a large number of acute and subacute inflammations of the fallopian tubes.