Is the joke that he can't be bothered to read labels or can't cook?
Panel one: A guy stands in his kitchen holding a hot pan over a stovetop. He holds his phone in the other hand and says, "Yea Mom, I'm cooking dinner."
Panel two: He opens the cabinet above his stove to look for something. He gets an unheard response on the phone and angrily replies, "I know how to cook Mom, I'm an adult!"
Panel three: He takes a second to look at the bottle he pulled out, the label reads "REAL POISON" and has a skull and crossbones on it.
Panel four: He pours the poison over his food and it sizzles. He continues talking on the phone saying, "So I'll see you next week?"