Flatulence happens. Activia has been reported to both cause and help alleviate flatulence, so there's no one answer for this question. I guess the potential is there, or people wouldn't say it happened to them.
As Activia claims to contain more fiber, flatulence can be expected as fiber aids in the digestive process. Bacteria in yogurt are also a factor in this.
Yes. Either caused due to a problem with lactose still present in the yogurt (yogurt is better tolerated than milk, but still an issue); or, a temporary readjustment of digestion.
