Classification of Poisons on the Basis of Mode of Action

Poison is asserted as a toxic substance that is harmful to living organisms, and its intake leads to severe health conditions. Inhalation of toxins leads to a disturbance within the body and affects the metabolism of the living organism too. Though sometimes, the effect of the poison is not severe, and the individual suffers from subtle health changes.

In Forensic Science, we have studied different types of poisons classified based on the mode of action and origin because of the difference in their respective properties.

What is the Mode of Action?

Mode of action is defined as a functional or anatomical modification at the cellular level arising from the exposure of a living organism to a material or a substance. It’s also asserted that a mechanism action describes such changes in a more efficient manner than the origin. The poisons classified under the mode of action often lead to severe necrosis or allergic problems, which turns to be highly lethal.

Let’s now discuss the 6 different types of poisons based on the mode of action and their different types and relevant examples.

Corrosive Poison

This group consists of strong acids and alkalis, which hampers the internal and external organs, tissues drastically, leaving a notable impact on the body systems of the living organism.

Examples of corrosive poison: Salicylic acid, Sulphuric acid, Nitric acid, Hydrochloric acid, Boron trifluoride, Phosphoric acid, Calcium Hydroxide, and Zinc Chloride.

Irritant Poisons

Irritant poisons lead to the accumulation of harmful gases within the body, due to which the organism suffers from nausea, excessive vomiting, severe pain, and irritation. These poisons could be seen through the naked eyes during the post mortem appearances, which depicts the redness/ulceration caused in the gastrointestinal tract.

This group of poison is further divided into three different categories, i.e., organic, inorganic, and mechanical poisons, respectively.

• Inorganic Irritant Poisons

Poisons under this category consist of both metallic and non-metallic toxins.

Examples of Inorganic Irritant poisons:- Arsenic, Zinc, Barium, Copper, mercury, antimony, Lead, Copper, and few radioactive substances.

• Organic Irritant Poisons

Poisons under this category comprise hazardous components derived from dangerous plants and animals that are fatal to humankind.

Examples of Organic Irritant poisons: 

(a) Venomous snakes, Sting bees or wasps, Spider ( animals ) 

(b)Castor, Aloes, Croton, Abrus precatorius, Anacardium Occidentale ( Plants) 

Mechanical Substances

Also known as mechanical irritants, these poisons lead to severe irritation and perforations in the gastrointestinal tract.

Examples of Mechanical substances: Chopped Hair Particles, Dried Sponge, Diamond Dust, Nails, Hair Pins, Hard Bricks, Coarsely Powdered Glass, etc.

Systematic Poisons

These poisons affect a significant system of the body and are further classified as Neurotic Poisons.

These poisons act on the body’s central nervous system and make the person feel weak and restless. 

• Spinal Poisons: These poisons act on the spinal cord.

Example: Nux Vomica and its alkaloids ( a stimulant ) and Gelsemium ( a depressant ) 

• Peripheral Poisons: These poisons act on the peripheral nervous system of the body. 

Example: Conium, Curare 

• Cerebral Poisons: These points act on the cerebrum part of the brain and depresses the brain area.

Example: Opium, Alcohol, Opioids

Antidepressants, Caffeine, Cocaine, Benzodiazepines, Dhatura and Belladonna.

Cardiac Poisons

Poisons that affect the cardiac system of the body are termed cardiac poisons.

Examples of Cardiac poison: Cyanide, Digitalis, Oleander, Aconite, Quinine, and Tobacco.

Asphyxiant Poisons 

This group of poisons leads to asphyxia and acts directly on the respiratory system.

Examples of Asphyxiant poison: Methane, Carbon Monoxide, Argon, Helium, Propane, Nitrogen, Carbon Dioxide, Arsine, Stibine 

Miscellaneous Poisons 

Such poisons which exhibit pharmacological reactions are considered miscellaneous poisons.

Examples of Miscellaneous poison: Analgesics, Tranquillizers, Street drugs, Antidepressants, Design drugs, and Antihistamines.

Final Words 

All these poisons have their significant characteristics, which forensic experts analyze during the medico-legal investigation of cases to extract the relevant information associated with the cause of death.