Abstract. We introduce the notion of an -combing and use it to show that hyperbolic groups satisfy linear isoperimetric inequalities for filling real cycles in each positive dimension. S. Gersten suggested the concept of metabolicity (over or ) for groups which implies hyperbolicity. Metabolicity admits several equivalent definitions: by vanishing of -cohomology, using combings, and others. We prove several criteria for a group to be hyperbolic, -metabolicity being among them. In particular, a finitely presented group G is hyperbolic iff for any normed vector space V and any .