Abstract We showed the use of the experimental chemical hardness in the analysis of the interaction between β -tubulin and epothilone B. The interaction is analyzed by exposing the Epothilone B to a sensor based on an organic self-assembled monolayer functionalized with Beta tubulin. The proposed methodology is nondestructive and label-free. It allows us to compare the interaction between Beta-tubulin and different concentrations of the pharmacological molecule, i.e ., epothilone B. The interaction is analyzed by the experimental hardness obtained according to the Miranda-Bueno methodology. We observed a linear behavior between the logarithm of the chemical hardness and the logarithm of epothilone B concentration. The results suggest the experimental chemical hardness can be used to compare the interaction of β -tubulin with epothilone B and with other pharmacological molecules.