Although vitamin E has been described as a source of allergic contact dermatitis (ACD), in only a few cases a true sensitization has been confirmed. We describe 2 cases of suspected ACD to vitamin E products. Patch tests and repeated open application tests were performed with the patients' own offending products. Then, patch tests with tocopherol acetate at different concentrations and further patch tests and repeated open application tests with a new sample of the product were carried out. Whereas the first sessions of tests gave positive reactions, the last sessions of tests performed with new samples were negative. Based on these results, we conclude that both our patients probably developed a true vitamin E ACD. However, as vitamin E exerts an anti-inflammatory effect and is an unstable molecule and its allergic potential change during the time, when ACD to vitamin E is tested a bimodal behavior of this molecule may be expected.