Joseph JA, Griffin MJ. Motion sickness: effect of the magnitude of roll and pitch oscillation. Aviat Space Environ Med 2008; 79:390–6. Background: Rotational oscillation in roll and pitch can cause motion sickness, but it is not known how sickness depends on the magnitude of rotational oscillation or whether there is a difference between the two axes of motion. Hypothesis: It was hypothesized that motion sickness would increase similarly with increasing magnitudes of roll and pitch oscillation. Method: There were 120 subjects (6 groups of 20 subjects) who were exposed to 30 min of 0.2-Hz sinusoidal roll or pitch oscillation at 1 of 3 magnitudes: 1) ± 1.83°; 2) ± 3.66°; or 3) ± 7.32°. Subjects sitting in a closed cabin with their eyes open gave ratings of their illness on a 7-point illness rating scale at 1-min intervals. Results: Over the six conditions, mild nausea was reported by 17.5% of subjects. With both roll oscillation and pitch oscillation, mean illness ratings were least with ± 1.83° of rotational oscillation and greater with ± 3.66° and ± 7.32° of oscillation. At none of the three magnitudes of oscillation was there a significant difference in motion sickness caused by roll and pitch oscillation. Conclusions: With rotational oscillation about an Earth-horizontal axis, there is a trend for motion sickness to increase with increasing motion magnitude. For the conditions investigated, similar motion sickness was caused by roll and pitch oscillation.