toxinssubstances

Toxins are poisonous substances that can cause harm to living organisms. They may be produced by living organisms themselves (biological toxins) or arise as chemical substances introduced into an environment. The term contrasts with toxicants, which are often man-made or not produced by living organisms.

Classification of toxins covers several categories. Biological toxins include bacterial toxins such as those produced by Clostridium and other bacteria; plant and animal toxins such as ricin from castor beans or aconitine from certain plants; and marine toxins such as saxitoxin and domoic acid. Mycotoxins are toxins produced by fungi, and exotoxic and endotoxins describe toxins related to bacterial secretions or cell-wall components, respectively, in some taxonomic frameworks.

Mechanisms of action vary widely. Toxins can inhibit enzymatic processes, disrupt cell membranes, interfere with nerve signaling, cause oxidative stress, or damage DNA and protein synthesis. The resulting effects range from rapid, acute illness to long-term, chronic conditions, shaped by dose, exposure route, and individual susceptibility.

Exposure routes include ingestion, inhalation, dermal contact, and injection. Risk management relies on proper labeling, safe handling practices, protective equipment, environmental monitoring, and regulatory controls administered by public health and regulatory agencies. Poison control centers provide guidance in suspected exposures.

In medical and scientific contexts, some toxins have therapeutic uses when administered in controlled doses, such as certain neurotoxins in very small quantities. Other toxins are primarily hazardous and subject to strict safety and regulatory oversight. Understanding toxins involves toxicology, risk assessment, and public health measures to prevent harm.