Welcome back. In this module, we're going to learn about poisonings, or toxicological ingestion. There's a whole field of medicine dedicated to the study of how the things we ingest usually accidentally, or in an attempt of self-harm, impact our bodies. This field is called toxicology. In EMS, you may encounter a patient who has ingested, or been exposed to something toxic in nature, or perhaps ingested too much of something that would otherwise be harmless. Within the same category, ingesting drugs and alcohol, can lead to medical emergencies as well. So, before we discuss specific substances and toxins, let's define some terms. A poison, is any substance that impairs health or causes death. You can come into contact with a poison by ingesting it, inhaling it, or having it come into contact with your skin. A poison can be in any elemental form, a liquid, a solid, or a gas. Thus, a poisoning is the exposure to a poison. While some may be in the case of intentional self-harm, suicide, or homicide, many of these actually happen accidentally, and many involve chilled. As mentioned, toxicology is the study of toxins, antidotes, and as mentioned, the effect of the toxins on the body. A toxin is a drug or substance that is poisonous to a human and will cause an adverse event, maybe even death. A toxin may not be poisonous if used properly, for example, opiate pain medication. However, if used inappropriately, it can cause harm. Conversely, some toxins are poisonous in all circumstances when they contact a human, such as sulfuric acid. There's no way to take or use this safely without harm. An antidote, is another term worth knowing. This is a substance that will neutralize the effect of the poison or a toxin. There are only a small number of poisons which have true antidote to reverse or neutralize the effects. While there are a variety of treatments and supportive care measures that can be implemented. Let's define a few more terms, specifically, the routes by which a poison can enter the body. First, ingestion. This is the swallowing of a poison, that then affects the body via absorption through the alimentary canal, or gastrointestinal tract. Next, inhalation. This is breathing a poison, and the exposure is typically a through a gas, vapor, or aerosolized substance. The damage can be directly to the lungs, but some poisons can enter the bloodstream via the capillaries at the alveolar level. Injection, is a poison that is injected into the skin subcutaneous area, or vein or a muscle. Finally, absorption is where a poisonous substance comes into contact via the skin. Another term or concept that you will hear, and that will help you identify patients, is a toxidrome. This refers to a set of signs and symptoms that is specific to a particular toxin. Certain toxins produced very reliably consistent findings when they affect a person, and it is useful to know those so you can provide appropriate care for the patient. Now, that we have an understanding of the basic terminology, we can further explore the common poisons that you will encounter in the field, how they affect the body, and how we will treat these patients.