© 2018 Society of Pharmaceutical Sciences of Ankara (FABAD). All rights reserved.The first use of biological warfare agents in history dates back to 14th century. While they were occupying the city Kaffa, the city water was first contaminated by throwing the death bodies of people infected with plague by Tatars. Later, many people died from plague and this event was known as the first use of biological weapons in history. Afterwards, smallpox virus was used as a biological weapon against the natives while occupation of America continent. In the Second World War, it is well-known that biological weapons were used in some fronts and on the slaves. Today, many countries possess biological weapons. Although smallpox virus was eradicated throughout the globe, it is still preserved in limited number of medical centers. As if live microorganisms and/or their spores can be used as biological weapons, toxins produced by these organisms also has the chance to be used as biological warfare agents. In this review, we will mention the history of biological weapon use, microorganisms (anthrax, plague, cholera, tularemia bacteria; smallpox, monkeypox, viral encephalitis and viral hemorrhagic fever viruses) and toxins (ricin, botulinum toxins and tricothesenes) that can possible be used as biological weapons. We will first give short information on microorganisms and toxins and later we will mention their pathophysiology, clinical outcomes after possible exposures, laboratory detection methods, diagnosis, treatment, prevention methods and decontamination.