This paper evaluates the influence of the type of solvent. medium on the activity of two linear and two branched poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) block co-polymers used to destabilize water-in-oil emulsions. These co-polymers were dissolved in xylene/ethanol (75:25) and toluene, which are commonly employed in commercial formulations, and water and solbrax/butanol (65:35) as a proposition of this work. The results show that the branched PEO-PPO co-polymer with hydrophilic segments (EO and OH) adjacent to each other performed best in breaking down the emulsions studied. This efficiency was better when the used solvent media was xylene/ethanol (75:25) or solbrax/butanol (65:35). The former solvent mixture improved the diffusion of the molecules of the additive in the oil phase of the emulsion and acted as a co-additive; the later only presented action as a co-additive.