What is acute toxicity?

• A. Adverse effects that persist over time after exposure, often irreversible.
• B. Adverse effects occurring within a few hours to a few days after exposure, often reversible.
• C. Symptoms that occur only at high altitude.
• D. The cost of treatment.

Answer: (B)

Acute toxicity refers to the adverse effects that appear soon after exposure to a substance, typically within hours to a few days, and these effects are often reversible once exposure stops and treatment is provided. This temporal pattern—rapid onset after exposure and potential reversibility—is what distinguishes acute toxicity from other types of toxic effects that develop over longer periods with repeated or chronic exposure. The option describing effects within a few hours to a few days after exposure and often reversible fits this definition best. The other statements describe outcomes that are long-lasting or irrelevant to exposure timing (such as altitude symptoms or cost), which do not define acute toxicity.