Many clinical trials have been conducted and reported no adverse effects with gamma oryzanol. It is likely safe when taken at normal doses, and it is not considered toxic or carcinogenic (cancer causing).
Because oryzanol is not an essential nutrient, recommended daily allowance levels have yet to be established. The bulk of research into oryzanol has used supplements ranging from 300 mg to 600 mg per day.
Some research suggests that gamma oryzanol taken in moderately high amounts (up to 600 mg per day) for several months can cause dry mouth, sleepiness, hot flushes, irritability, and light headedness in some individuals.
But If you don’t take them over dose, it is considered very safe to people. If such side-effects occur, patients should consult with a health care provider about lowering dosage or stopping use of oryzanol.But If you don’t take over dose of gamma oryzanol.