Various types of biological warfare (BW) have been practiced repeatedly throughout history. This has included the use of biological agents (microbes and plants) as well as the biotoxins, including venoms, derived from them. Before the 20th century, the use of biological agents took three major forms: * Deliberate contamination of food and water with poisonous or contagious material * Use of microbes, biological toxins, animals, or plants (living or dead) in a weapon system * Use of biologically inoculated fabrics and persons