The simplex centroid mixture design for the ethanol, dichloromethane, hexane and acetone solvents has been applied to the extraction of crude mass and the fiber, organic, neutral and basic fractions as well as the fractionation residues of Erythrina speciosa Andrews leaves. Binary and ternary synergic solvent interactions are seen to provide dominant contributions to the extraction of both crude mass and all the fractions. Quadratic and special cubic mixture models precisely predict the extracted quantities of each fraction and the residue as a function of the proportions of the four solvents. Different solvent mixtures are found to be the most efficient extractors for the different fractions: binary dichloromethane-hexane mixtures for the fiber fraction, ternary ethanol-dichloromethane-acetone mixtures for the neutral fraction, binary ethanol-dichloromethane mixtures for the organic fraction, crude extract and residue values and ternary ethanol-dichloromethane-hexane mixtures for the basic fraction. Principal component analysis shows that the ethanol-dichloromethane mixtures are important for extracting large quantities of the basic and organic fractions as well as of the residue and crude masses.