This electronic document is a “live” template and already defines the components of your paper Simulation and optimization of the drying process may require the calculation of the water diffusivity of the product. In this work we have described the estimation of the coefficients of diffusion of the moisture in the henna leaves from the drying curves obtained with DVS device. Two different methods can be used to evaluate this coefficient (analytical method and numerical method). In this application note, we discussed the method based on the analytical solution of a Fick diffusion model which allowed the determination of the diffusion coefficient by simple linear regression on the experimental data. The results obtained showed that the diffusivity is not strongly dependent on the water content of the product. On the other hand, it increases well with the increase in the temperature of the product.