The known fundamental symmetries and interactions are well described by the Standard Model. Features of this powerful theory, which are described but not deeper explained, are addressed in a variety of speculative models. Experimental tests of the predictions in such approaches can be either through direct observations at the highest possible accelerator energies or through precision measurements in which small deviations from calculated values within the Standard Model are searched for. Antiproton physics renders a number of possibilities to search for new physics.