Like many of Dario Argento's giallo films, while blood and gore is displayed in brutal fashion and often shown in copious amounts, it's intentionally stylized. The blood is very saturated in color (sometimes it even looks pink), and it pours unrealistically.
A lot of the violence is rather quick, but it is usually accompanied by a lot of blood.
A man's clothes get hooked onto a truck. It drives, dragging him across the road and eventually making his neck break on a sidewalk. His head is then squashed by an incoming car (offscreen). Fairly disturbing.
A woman's head is smashed through a window. The glass shards sink into her throat, causing blood to spurt out.
A woman is beaten unconscious, then she is drowned in a bathtub of scalding hot water that burns and maims her face.
A man has his teeth broken by being thrown against a table and a piano; he is then stabbed in the neck.
A man finds the remains of a human corpse hidden in the walls of a house. The corpse is rotting.
A woman is stabbed offscreen and shown moments later with a knife in her abdomen (she is still alive).
A woman accidentally kills one of her pet birds.
A woman stabs her husband in the back in front of their child. The child then grabs the knife and stares at the dripping blood.
A girl suddenly kills a lizard.
A woman's necklace gets stuck in an elevator gate. The elevator moves up, causing the necklace to slice into her neck. It is heavily implied that she's decapitated, but this isn't shown.
Several somewhat disturbing images of dolls being hung, puppets with needles in them, and paintings that look like they were done by a child depicting violent and bloody acts.