The "B" and "R" in "B&R grenade" stand for "Barf" and "Run" respectively. It's a mild nerve gas grenade designed to incapacitate the enemy. The "barf" part should be obvious. The "run" part pertains not to "running way," per se, but to runniness as a condition. And that's probably more information than you needed.

If any of you are worried about the grenade, you should be. Worried about the grenade, that is. Those for whom it was intended need none of your worry. The grenade, however, got a nice plasma bath, which tends to be a bit harsh on complex organic molecules.