In a standardized way three different methods of measuring nausea have been assessed in 849 patients enrolled in 4 double blind, randomized, clinical trials, and 2 observational studies. Nausea was measured before and 2, 4, 6, 8 and 24 hours after cancer chemotherapy by using a discrete scale (DS), a visual analogue scale (VAS) and a continuous chromatic analogue scale (ACCS), and it was evaluated according to 4 different dimensions: maximal intensity (MI) entity (E) duration (D) and quantity (Q). The distributions of nausea measurements in the population, agreement between the scales and their sensitivity, and agreement between dimensions and their sensitivity were analyzed. A uniform distribution of nausea measurements was found only in patients receiving chemotherapy without any antiemetic treatment. There was substantial equivalence of the different scales, and no advantage was shown an using an analogue (VAS) than a discrete (DS) scale. A trend toward increasing sensitivity in detecting differences as the dimensions of nausea considered became more inclusive of the various aspects of this symptom (Q more sensible than E more sensible than MI) was observed.