In health and related fields, the term lethal dose refers to the amount of a medicine or substance that is considered to be lethal or that will cause death, usually after a short time. This dose is used in toxicology and especially in toxicity tests to analyze the effect of a certain substance in organisms. Additionally, the lethal dose varies according to the species and there are slight variations between organisms. For example, substances such as chocolate are generally safe for humans but in many other species, a small quantity of chocolate is a lethal dose. According to this, the dose that causes death in the animal during toxicity testing is the lethal dose.