The pressure-transmitting medium in a high-pressure experiment is usually thought of as an inert medium that allows the sample to be compresses rather than crushed. In organic materials, the choice of medium can alter the crystal structure of the sample depending on the solubility. P-aminobenzoic acid is a well-known organic substance that is used extensively to explore polymorphism and crystallisation. In this experiment we will investigate the pressure-transmission medium and the way in which the material reacts to compression in the medium. Our Raman studies have shown that in water, ethanol and a 50% mixture of each, p-aminobenzoic acid can either undergo a phase transition to a new high-pressure phase or remain in the known form. We will follow these experimental observations with diffraction measurements so that structural information can be elucidated.