Cardanol, which is a naturally occurring C-15,, unsaturated aliphatic chain-substituted phenol derived from cashew nut shell liquid, was used as a dispersant for alumina in toluene. Adsorption data, along with the results of sedimentation studies, green density, and slurry viscosity (as a function of dispersant concentration), suggest that cardanol adsorption initially proceeded through surface coverage by a phenolic group that lies flat on the surface and that the best powder dispersion occurred at surface saturation by more closely packed end-on adsorbed cardanol molecules. The alkyl-chain unsaturation significantly contributed to dispersion, such that the saturation by hydrogenation led to an increase in the slurry viscosity by a factor of similar to 2,5, Concentrated slurries generally showed shear-thinning flow behavior, and the measured viscosity of a highly concentrated (53 vol%) slurry was <1 Pa.s at a shear rate of 93 s(-1).