Effects that persist in a biologic system for only a short time, generally less than a week. The effects might range from behavioral or color changes to death. Tests for acute effects are performed with humans, animals, plants, insects, and microorganisms. Intoxication and a hangover resulting from the consumption of too much alcohol, the common cold, and parathion poisoning are examples of acute effects. Generally, little tissue damage occurs as a result of acute effects. The term acute effects should not be confused with acute toxicity studies or acute dosages, which respectively refer to short-term studies (generally less than a week) and short-term dosages (often a single dose). Both chronic and acute exposures can initiate acute effects.