It's in the prescribing information.[1]

Adverse event - Xofluza(%) - Placebo(%)

Diarrhea - 3% - 5% [higher in placebo]

Bronchitis - 2% - 4% [higher in placebo]

The FDA requires that the manufacturer list the most common adverse events, even if they are unrelated to the drug in question.

[1]https://www.gene.com/download/pdf/xofluza_prescribing.pdf