An analysis of the arm-interarm and large-scale spatial O/H variations in a sample of four normal and three barred late-type spiral galaxies, using data previously published, is presented. Within the limits of the intrinsic uncertainties affecting the O/H values derived from nebular line ratios calibrated by semi-empirical methods, there is no evidence that the chemical composition of the interarm H II regions differs from that observed in the regions located in the spiral arms. For two radial ranges of galactocentric distances in each object, we also show that no marked azimuthal asymmetries in abundance (i.e., < 0.2 dex) are observed across the disks of galaxies of our sample. According to Roy & Kunth, these results suggest that azimuthal mixing processes (induced by the differential rotation and by supershell expansion) are able to wipe out the larger O/H inhomogeneities in the interstellar medium of the disks of spiral galaxies in a few galactic rotations.
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