The local field contribution to some three- and four-level coherent atomic vapors is considered, and a significant modification to optical properties due to dipole-dipole interaction between neighboring atoms is discussed. It is found that the local field effect can reduce loss of a four-level N-type vapor medium at the resonant frequency in both the steady and transient cases. In order to achieve a left-handed medium with a negative refractive index, a scenario to realize simultaneously negative permittivity and permeability inside a mixed coherent atomic vapor by using quantum coherence effect is suggested. One of the remarkable features of the present scheme is such that it can lead to a controllable manipulation of negative refractive index of an atomic vapor by using external coupling and signal fields. This may be a new scheme to fabricate the negatively refracting materials based on quantum optical approach.