A study was made of how different cyclodextrin (CD) derivatives, such as alpha-CD, beta-CD, gamma-CD, dimethyl-beta-CD and random-methyl-beta-CD, influence the diffusion of paracetamol. For interpretation of the phenomena, dissolution rate investigations, measurements of surface tension and determinations of partition coefficients were also performed. It was established that paracetamol has a low diffusion ability. It was also found that the different CD derivatives exert their influence in diverse ways, which depend on, among others, the cyclodextrin ratio and the mode of preparation of the product. These complementary examinations are useful for an explanation of the phenomena.