Poisoning occurs when a person is exposed to a harmful substance—such as chemicals, medications, toxic plants, gases, heavy metals, or contaminated food—in amounts that damage the body’s tissues or disrupt normal function. Exposure may happen through ingestion, inhalation, skin contact, or injection. Symptoms vary widely depending on the substance involved and the level of exposure but can include nausea, vomiting, abdominal pain, confusion, difficulty breathing, seizures, or loss of consciousness. Some poisons act rapidly and cause acute symptoms, while others accumulate gradually and lead to chronic health effects. Because poisoning can become life-threatening, especially in children or with high-dose exposure, prompt medical evaluation or contact with a poison control center is critical when exposure is suspected.