I previously responded to a very similar question on whether it is safe to drink Roundup. As with most household and consumer products, Roundup should be handled appropriately, following the product’s labeled directions. You can read the related response here, and an excerpt is below.
“Most of us have picked up a bottle of Roundup from a home center and used it to kill weeds in our driveways and gardens. Roundup-brand herbicides have a long history of safe use at home and in agricultural settings. As with most chemical products, appropriate precautions must be taken during handling and use of these products and the directions for use must be followed carefully. Almost all nonfood products, including herbicides, would not be safe for human consumption straight out of the container, because most chemical products contain ingredients at levels significantly higher than would be acceptable for daily human consumption.
“Drinking dishwashing detergent or shampoo out of the container, for example, is not advised, because these chemical products contain surfactants that should not be intentionally consumed, yet low levels of dishwashing detergent and shampoo residues are consumed daily off of cups, plates and utensils and during showering, without adverse health effects. And, rightfully so, people are not concerned about use or consumption of trace amounts of detergents.
“The same is true for herbicides. Roundup-brand products also contain surfactants like those found in dishwashing detergents and shampoos and, like these consumer products, should not be intentionally consumed. However, low levels of these surfactants, and the active ingredient in Roundup-brand products (glyphosate) that gives it its weed-killing power, ingested from the food we eat are well below what has been determined as acceptable for daily human consumption.”