Which of the following correctly describes toxicity?

Toxicity is defined as the degree to which a substance can damage an organism, and in the context of medication, it specifically refers to the harmful effects that can occur when a drug is administered in excessive dosages. This can happen when the amount of medication given exceeds the therapeutic range that the body can safely tolerate, leading to an adverse drug reaction. Understanding toxicity is crucial for healthcare professionals, as it helps them to monitor patients and adjust dosages to prevent harmful effects from medication.

In contrast, the other choices describe aspects that do not align with the definition of toxicity. A normal drug reaction refers to expected effects of a medication when administered appropriately. Effective drug treatment implies that the medication serves its intended purpose without causing harm, while minor side effects denote less severe reactions that are often manageable and do not pose significant risk, contrasting sharply with the potentially dangerous implications of toxicity.