Activia is a low-fat probiotic yoghurt-like drink produced by Danone (Dannon in the U.S.), either a semi-solid yoghurt or a yoghurt drink and sold in small and larger packages in more than 30 countries worldwide. Activia contains the probiotic bacterium Bifidobacterium animalis. It also contains vitamin B12 and calcium.

Activia is available in plain, strawberry, peach, mango, oatmeal, pear, walnut, coconut, vanilla, blueberry, prune, fig, pineapple, aloe vera, fibers, fruit of the forest, kiwi cearals and rhubarb varieties.

Danone claims that the "Bifidus regularis" or "Bifidus actiregularis" (both are brand names of Bifidobacterium animalis) helps digestive discomfort and irregularity. The brand names are seen as a marketing ploy to create a more identifiable term in the public view of the bacterium, which possibly creates a false sense of functionality with the product.

Activia is in the emerging category of functional foods designed to address digestive health. Such products typically contain a proprietary strain of probiotics and may also contain prebiotics.

A lawsuit filed in a Los Angeles federal court on January 25, 2008 said Dannon's own studies failed to support its advertised claims.

In a statement in response to the lawsuit in January 2007, Dannon stated that it, "strongly disagrees with the allegations in the lawsuit" and that it makes all scientific studies about its products available to the public following the established method of peer-review and publication.