In "Dare Day", Clarence and Sumo get seriously injured after they did extreme dares.
In "Fun Dungeon Face Off", Clarence and Jeff fight on top of a fast food playground during the climax which parodies Star Wars Episode III with foam sticks but it's non-brutal.
In "A Pretty Great Day With a Girl", Clarence and some other kids have a fight throwing moss, mud, and other stuff found around them but it's non-brutal.
Many episodes so far have Clarence and the other kids causing havoc and property damage but its played comically.
In "Man of the House", Clarence, Jeff, and Sumo create burglar traps in the house. When Chad enters in, they try to stop him getting caught in there traps which hit the kids instead. Chad later gets hit in the legs with the last trap shown and is sent to the hospital.
Three episodes have a character named Joshua getting physically injured in some way. He gets scars on his right cheek after being attacked by Sumo in a flashback in "Lost in the Supermarket", gets his ear partially bitten off from a goat (offscreen by the way) in "Nature Clarence", and gets his right eye jabbed with a fork (offscreen again) after slipping in "Neighborhood Grill".
Scatological humor is present, and vomit is implied but not on-screen.
In "Bedside Manners" an alive heart is seen but it's very unrealistic.