A more thorough explanation:

An intervening cause is an event that occurs after a dangerous or improper action by a party and before the harm that could have been caused by the action. This event breaks the chain of causation between the original act and the injury to the victim. The presence of an intervening cause can mean that the person who started the chain of events may no longer be held responsible for the damages to the injured person since the original action is no longer the proximate cause.

In the case of State v. Smith in Ohio, the defendant punched the victim in the head, causing the victim to hit his head on a nearby car and then the pavement. The victim was rushed to the hospital for his head injuries, but he refused to get a CAT scan. His head injuries persisted, and he continued to feel sick and confused when he returned home. He failed to take his insulin, and days after the punch, the victim died. The court found that the victim's failure to take his insulin was not an intervening cause since the punch caused the victim to fail to take his medicine through the mental injuries. The defendant was found guilty of homicide.

This example illustrates how an intervening cause can break the chain of causation between the original act and the harm to the victim. In this case, the victim's failure to take his insulin was not considered an intervening cause since it was caused by the mental injuries resulting from the punch.