Mycotoxins are toxic substances which are produced by fungi, usually as secondary metabolic products. These toxins are of great interest to humans because they can cause sickness or even death in people, but they can also be put to a variety of uses. Some Penicillium molds, for example, produce mycotoxins which are harmful to bacteria. The study of mycotoxins has progressed in leaps and bounds in the laboratory since the mid-20th century, when people started realizing the extent of mycotoxins in the environment.
The production of toxins is not uncommon in nature. Many organisms make toxins to make themselves less appealing, ensuring that they will live to pass on their genetic material, rather than being eaten. In other instances, the toxin is a purely accidental byproduct of the organism's metabolism. Fungi generate some toxins by accident in the process of building the amino acids they use to digest the materials they eat. Somewhat unusually, fungi digest things before eating, releasing amino acids onto organic matter to break it down before they consume it.
Poisonous mushrooms are famous among humans for their mycotoxins. A large number of mushrooms contain compounds which cause gastrointestinal distress, but some have more dangerous toxins, such as alpha-amanitin, the mycotoxin present in some
Awareness about the mycotoxins produced by molds has also grown since the 1980s, when people first began to recognize the risk of dangerous molds. Certain molds which infest walls, carpeting, and so forth produce mycotoxins which can be hazardous if touched, inhaled, or consumed. People who have gotten sick from mold exposure have successfully sued for damages in some instances, arguing that the manufacturer or owner of a structure failed to build and maintain it properly, inviting the invasion of mold.
Toxins produced by fungi were also known in the ancient world. Ergot, a fungus which infests cereal grains, famously produces a toxin which causes a variety of colorful symptoms. Some people historically ingested ergot deliberately with the goal of enjoying its psychotropic effects, and some other fungi are consumed in the modern era for much the same reason.
Symptoms of exposure to mycotoxins vary considerably, because they are so diverse. The effects of mycotoxins can also vary depending on the amount and duration of exposure. Many mycotoxins affect the nervous system, causing symptoms like dizziness, clumsiness, blurred vision and confusion, but these symptoms do not appear in all cases or with all mycotoxins.