Poisons are commonly noticed in killings, suicides, and accidents cases. They play an important function as the silent weapon that destroys life in a strange and covert manner.

Poisons can be divided into two categories according to their action and Use.

According to the Site and Mode of Action

There are four categories of action of poison according to their site and mode of action

Also Read: Forensic Toxicology

1. Local Action

Local Action means direct action on the affected site of the body. This can be divided into three categories:

A.) Corrosive

►Strong Acid: Mineral Acid and Organic acid

►Strong alkali Metallic: Mercuric Chloride

B.) Irritant

► Mechanical:  Glass Powder

C.) Chemical

► Inorganic: Weak Acid, Weak Alkalies, Inorganic Non-Metals, And Inorganic Metals.

► Organic: Chemical preparations, Animal and Vegetable Origin

2.  Remote Action

Remote action affects the person due to absorption of tat poison into the system of that person. This can be divided into following categories:

Neurotics

• C.N.S. Poisons

i. Somniferous – These types of drugs induce sleep (Such as; Opium and its alkaloids, Barbiturates)

ii. Intoxicant – A substance that causes intoxication or inebriation. (Alcohol, ether, and chloroform, for example)

iii. Stimulant – A type of medication that speeds up the transmission of signals between the brain and the body. (Amphetamines, Cocaine, Ecstasy, Nicotine, Caffeine, and so on)

iv. Deliriant – These types of substances causes delirium (Such as; Dhatura, Belladona, Hyocyamus, Cannabia Indica)

v. Hallucinogens – Affects perception, thinking, and emotion. (LSD, Mescaline, Psilocybin, and Mescaline, for example)

vi. Convulsant – Causes convulsions and/or epileptic seizures.

vii. Stupefying Poison – Causes a person to lose their ability to think clearly or be attentive to their environment.

• Spinal toxins (Convulsant) (Strychnos Nux Vomica)

• Peripheral Nerves

a. Local Anaesthetics: Cocaine, Procaine.

b. Relaxants.

• Cardiac Poisons

Cardiac Poisons have a detrimental effect on the heart’s function.

(Such as; KCN, NaCN, Digitalis, Aconite, Nicotine, Quinine, Oleander)

• Asphyxiants

These causes Oxygen deprivation. Oxygen deprivation can cause unconsciousness and, in severe cases, death.

(Such as; Carbon Dioxide, Carbon monoxide, Hydrogen Sulphide)

• Nephrotoxic

Kidney damage or harm as a result of poisoning.

(Such as; Oxalic Acid, Mercury, Cantherides)

• Hepatotoxic

Due to toxicity, the liver is damaged or injured.

(Such as; Phosphorus, Carbon tetrachloride, Chloroform)

Miscellaneous Poison

Food Poisons.

3. Local and Remotes action

Some toxins have the ability to harm both local and remote organs.

(Such as; Oxalic Acid)

4. General Action

Some poisons have the ability to harm many body organs.

(Such as; Mercury, Arsenic, and other heavy metals, for example.)

Classification of Poison according to motive or nature of use:

√ Homicidal: Arsenic, Aconite, Digitalis, Abrus Precatorius, Strychnos nux vomica.

√ Accidental: Aspirin, Organophosphorus, Copper Sulphate, Snakes Bite, Ergot, CO, CO₂, H₂S.

√ Suicidal: Opium, Barbiturate, Organophosphorus, Carbolic Acid, Copper Sulphate.

√ Abortifacient: Ergot, Quinine, Calotropis, Plumbago.

√ Stupefying Agent: Dhatura, Cannabis, chloral hybrate.

√ Agents used to cause Bodily Injury: Corrosive acids and Alkalies.

√ Cattle Poison: Abrus precatorius, Calotropis, Plumbago.

√ Used for Malingering: Semicarpus Anacardium