Use of hydroxyoleic acid and its analogous compounds in the manufacture of drugs. Describes the use of hydroxyoleic acid and its analogs of general formula I: COOH--CHR--(CH.sub.2).sub.m--CH.dbd.CH--(CH.sub.2).sub.n--CH.sub.3, in which m and n have, independently, a value of 0-15 and R can be any residue with molecular weight below 200 Da, in the manufacture of drugs that can be used in the treatment of cancer, hypertension, obesity or diseases mediated by alteration of the membrane structure and the consequent regulation of G-proteins or of the receptors coupled to them.