Experiments tell that the emulsification of mineral oils by lecithins, or glucosides, requires the addition of alcohols as cosolvents. In our first studies we used alkanols for this purpose. However, for preparing nontoxic microemulsions with biological oils, the alkanols, too, must be substituted by nontoxic alcohols. In this paper we show that n-alkane-1,2-diols (C-i-diols) are efficient substitutes, with medium-chain diols (i less than or equal to 6) playing the role of propanol and the longer-chain C-8-diol that of butanol. After having recently demonstrated how to prepare microemulsions with a long-chain lecithin and C-5-diol, we show in this paper how to prepare nontoxic microemulsions with a long-chain monoglucoside and C-8-diol.