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Comprehensive Toxicology Notes (Forensic Medicine)

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1. LEAD (Plumbum / Pb)

• Soft, bluish-grey, heavy metal
• Compounds used as poisons: Lead acetate (sugar of lead), lead carbonate (white lead), lead monoxide (litharge), red lead (Pb3O4), lead sulphide
• Hydrochloric acid produces a white precipitate soluble in boiling water, crystallizing on cooling (diagnostic test)

• Inorganic metallic poison; heavy metal; cumulative poison

• Acute: ~450-500 mg of lead acetate; chronic - no fixed safe threshold
• Blood lead >70 µg/100 mL is considered severely toxic

• Acute poisoning: several days to weeks
• Chronic poisoning: months to years (cumulative)

1. Lead missiles (bullets) embedded in tissues may cause delayed lead poisoning - important in forensic investigation of gunshot injuries
2. Detection of lead in hair, bone, and tissues at autopsy is used to confirm lead poisoning as cause of death in criminal/medico-legal investigations

1. Battery manufacturing, plumbing, paint (white lead, red lead) - occupational/industrial use
2. Diachylon paste (lead oleate) historically used as an abortifacient

• Acute: Metallic taste, burning abdominal pain, vomiting, constipation
• Chronic (Plumbism/Saturnism):
  • Facial pallor (especially around mouth - due to vasospasm)
  • Anaemia with punctate basophilia (stippled red cells)
  • Burton's/Lead line: bluish-black line on gums at junction with teeth (lead sulphide deposits near carious teeth)
  • Lead colic: severe intestinal, ureteric, uterine colic, worse at night
  • Constipation (classic)
  • Lead palsy: wrist drop (radial nerve - extensor muscles of wrist), foot drop; tremors, hyperesthesia
  • Lead encephalopathy: headache, irritability, insomnia, convulsions, delirium, coma (more in children)
  • Renovascular: Fanconi syndrome, interstitial nephritis, hypertension
  • Reproductive: oligospermia, infertility, miscarriage
  • Children: low IQ, cognitive impairment, premature birth, delayed growth

• Inhibits delta-aminolevulinic acid dehydratase (ALAD) - disrupts haem/porphyrin synthesis
• Inhibits 5-pyrimidine nucleotidase - impairs RNA degradation in RBCs - basophilic stippling
• Substitutes for calcium at synapses and in bone
• Inhibits Na-K ATPase and other enzymes
• Causes peripheral axonal neuropathy (demyelination + axon degeneration)

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2. ARSENIC

• Arsenic trioxide (white arsenic / As2O3): white, odourless powder with sweetish taste; most commonly used
• Other compounds: sodium arsenate, copper arsenite (Paris green), lead arsenate
• Marsh's test, Reinsch's test, Gutzeit test for detection
• Hair and nails accumulate arsenic (keratin affinity)

• Inorganic metallic poison; protoplasmic and capillary poison; cumulative

• Arsenic trioxide: 180 mg (but doses as low as 30 mg have been fatal; individual tolerance varies widely)

• 12-48 hours after ingestion; may be fatal within 2-3 hours with large doses

1. Hair, nail, and urine analysis (ion emission spectroscopy) for diagnosis and medico-legal proof of chronic arsenic poisoning (Mees' lines in nails are pathognomonic)
2. Marsh's test on stomach contents / exhumed tissues to establish homicidal/suicidal arsenic poisoning in court

1. Pesticides/insecticides (Paris green - copper arsenite), wood preservatives
2. Historically used in Fowler's solution (1% arsenious trioxide) as a tonic/medicine; used by homicides due to tastelessness and resemblance to flour

• Acute (within 30 min):
  • Metallic taste, garlicky odour (characteristic), dry mouth, dysphagia
  • Severe nausea, projectile vomiting (dark brown/yellow, with blood and mucus)
  • Profuse diarrhoea - rice-water stools (resembles cholera), bloody in some
  • Intense thirst, burning pain in throat and stomach
  • Increased salivation, periorbital oedema
  • Cramps in calf muscles, restlessness
  • Cyanosis, cold clammy skin, hypoxia, convulsions, coma
  • Acute tubular necrosis, haematuria, oliguria, proteinuria
  • ECG: prolonged QT interval, T-wave inversion
  • Death from irreversible circulatory insufficiency
• Subacute/Chronic (2-4 weeks after non-lethal dose):
  • Hair loss (alopecia)
  • Mees' lines: white transverse lines on nails (appear up to a year after poisoning)
  • Sensorimotor peripheral neuropathy
  • Skin: raindrop pigmentation (melanosis), hyperkeratosis of palms and soles, Bowen's disease
  • Hepatitis, cirrhosis, ascites (Fowler's solution)
  • Renal failure

1. Combines reversibly with sulfhydryl (-SH) groups in tissue proteins
2. Interferes with enzyme systems essential for cellular metabolism (pyruvate oxidation, Krebs cycle)
3. Capillary poison - dilates capillaries - plasma transudation, hypovolemic shock
4. Fatty degeneration of liver
5. Hyperaemia and haemorrhages in intestinal mucosa (vesicle formation, sloughing)
6. Renal tubular necrosis
7. Peripheral nerve: disintegration of axis cylinder (axonal neuropathy), fragmentation and resorption of myelin

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3. SEEDS OF ABRUS PRECATORIUS (Jequirity / Rosary Pea / Gunchi / Ratti)

• Seeds: oval, egg-shaped, 8 mm long × 6 mm broad; bright scarlet red with a large black spot at one end (hilum); weigh ~105-120 mg
• Tasteless and odourless
• Also known as: Indian liquorice, Crab's eye, Gulganji
• Active principle: Abrin (a toxalbumin/phytotoxin)
• Seeds may occasionally be all black, white, yellow, or blue

• Vegetable/organic irritant poison; toxalbumin (phytotoxin); acts like bacterial toxin

• 1-2 seeds by mouth (decorticated/powdered)
• 90-120 mg of abrin by injection

• 3-5 days

1. Malingerers use powdered seeds to produce artificial conjunctivitis - detection is important in medico-legal cases
2. Suis (poisoned needles made from abrus powder + opium + dhatura paste) used to kill cattle; identification of sui at injury site is key forensic evidence in cattle-poisoning cases

1. Used as arrow poison by tribal communities
2. Used as an ornamental/decorative bead in jewellery (rosary beads) - inadvertent puncture risk

• When seeds are swallowed whole (raw or cooked): usually not poisonous (intact testa prevents absorption)
• When injected / applied to wound (via sui):
  • Local: painful swelling, ecchymosis, oedema, necrosis, haemorrhagic fluid from puncture
  • Systemic (resembles viper bite): vertigo, cardiac arrhythmia, convulsions, coma, death
  • Animal: apathy, drowsiness, refusal of food, unable to move after 3-4 days, coma and death
• When ingested as extract/powder:
  • Nausea, vomiting, colicky abdominal pain, diarrhoea, haemorrhage, collapse

• Abrin inhibits protein synthesis by inactivating the 60S ribosomal subunit (same mechanism as ricin - depurination of 28S rRNA)
• Causes agglutination and lysis of red blood cells (haemagglutination)
• Acts like viperine snake venom (haemorrhagic, cytotoxic)
• Antigenic properties - can raise antibodies (anti-abrin)

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4. FRUITS OF SEMECARPUS ANACARDIUM (Marking Nut / Bhilawan / Bhilwa)

• Fruit: black, heart-shaped (cone-shaped) with rough projection at base; thick cellular pericarp
• Juice: brownish, oily, acrid; turns black on exposure to air (used by washermen as marking ink)
• Active principles: Semecarpol (0.1%) and Bhilawanol (15-17%)
• Also called Marking nut tree

• Vegetable/organic irritant poison; vesicant and corrosive

• 5-10 gm

• 12-24 hours

1. Juice applied to skin produces blisters resembling bruises (artificial bruise) - important in medico-legal cases involving false charges of assault; must be differentiated from true bruise
2. Juice used to introduce into vagina as punishment for infidelity - constitutes criminal assault; detection is medico-legal evidence

1. Used by washermen (dhobis) as marking ink on clothes
2. Used in Ayurvedic/traditional medicine for paralysis and pain relief (Vaidya's administer juice)

• External application:
  • Irritation, painful blisters containing acrid serum
  • Eczematous eruption spreading to adjacent skin, itching
  • Lesion resembles bruise, may ulcerate and slough
• Internal ingestion (large doses):
  • Blisters in mouth and throat
  • Severe gastroenteritis
  • Dyspnoea, tachycardia, hypotension, cyanosis
  • Absence of reflexes, delirium, coma, death

• Bhilawanol acts as a direct contact irritant and vesicant on skin and mucous membranes (chemical burn mechanism, similar to urushiol of poison ivy - same Anacardiaceae family)
• Internally: direct irritation of GI mucosa causing haemorrhagic gastroenteritis
• Systemic absorption causes autonomic and cardiovascular toxicity

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5. CROTON SEEDS (Croton tiglium / Jamalgota / Nepala)

• Seeds: oval, blackish-brown colour with white oily kernel; have longitudinal lines on them
• Resemble castor seeds in size/shape (small) but differ in appearance
• Oil: brownish, viscid, unpleasant smell, bitter taste
• Active principle: Crotin (toxalbumin - irritant and vesicant); also crotonoside (glycoside, less poisonous)
• Oil contains powerful vesicating resin (crotonoleic acid, methyl crotonic acid)

• Vegetable/organic irritant poison; toxalbumin

• Seeds: 4-5 seeds
• Oil: 1-2 mL (20 drops of oil)

• 6 hours to 3 days (may be as early as 4-6 hours or delayed up to 6 days)

1. Used with homicidal intent - mixed in food; identification of seeds/oil in stomach contents is forensic evidence
2. Used as abortifacient - taken internally or applied locally; medico-legal significance in criminal abortion cases

1. Used in traditional/folk medicine as a purgative (in small doses)
2. Used as arrow poison by wild tribal communities

• Hot burning pain from mouth to stomach
• Salivation, nausea, copious vomiting
• Powerful purging/diarrhoea with burning pain at anus
• Vertigo, prostration
• External skin application: burning, redness, vesication (blistering)
• Collapse, coma preceding death

• Crotin (toxalbumin): inhibits ribosomal protein synthesis (similar to ricin/abrin) - cell death
• Acts as a direct local irritant and vesicant on skin and GI mucosa
• Causes severe inflammatory reaction with oedema, erosion, haemorrhage in GI tract
• Oil component (phorbol esters related to croton oil): activate protein kinase C - acts as tumour promoter; causes intense local inflammation

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6. SEEDS OF RICINUS COMMUNIS (Castor Seeds / Ricin)

• Seeds: oval, glossy brown, mottled (speckled); two sizes (big and small)
• Small seeds resemble croton seeds (~1.25 cm long × 0.85 cm broad)
• Active principle: Ricin (supertoxic toxalbumin/phytotoxin)
• Castor seeds are poisonous when eaten raw; harmless when swallowed whole (intact testa) or after cooking
• Extracted castor oil does NOT contain ricin (non-poisonous)
• Residual press cake (after oil extraction) is highly poisonous (contains ricin)

• Vegetable/organic irritant poison; toxalbumin (phytotoxin); supertoxic

• 6 mg of ricin (equivalent to ~10 seeds)
• By injection: as little as 1 µg/kg body weight (bioweapon dose)

• Several days (multi-organ failure is delayed)

1. George Markov assassination (London) - ricin-filled pellet fired from umbrella tip - represents political assassination weapon; detection in autopsy tissues is forensic evidence
2. Used by terrorists - poisoning of water/food or ricin-laced projectiles; used as potential bioweapon; its identification is a forensic/national security matter

1. Castor oil used commercially as a lubricant, in cosmetics, and in Ayurvedic medicine (purgative)
2. Powder of seeds used to produce local irritation of skin/mucous membranes (by criminals to cause harm)

• Ingestion of raw seeds:
  • Burning in throat, salivation, nausea
  • Copious and painful vomiting
  • Colicky abdominal pain
  • Bloody purging (haemorrhagic diarrhoea)
  • Dehydration, cramps
  • Coma and convulsions preceding death
• Dust inhalation (occupational): Dermatitis, conjunctivitis, rhinitis, asthma, allergy
• Injection (bioweapon): Multi-organ failure, haemorrhage, death

• Ricin is a Type II ribosome-inactivating protein (RIP)
• A-chain (ricin toxin A chain): N-glycosidase activity - cleaves a specific adenine residue from the 28S rRNA of the 60S ribosomal subunit (depurination) - permanently inactivates ribosomes
• B-chain: lectin - binds to galactose residues on cell surface glycoproteins/glycolipids - facilitates endocytosis of ricin into cells
• Result: complete inhibition of protein synthesis - cell death
• No specific antidote exists

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7. CAPSICUM SEEDS (Chilli / Lalmirch)

• Seeds: ~0.30 cm long and wide; pale yellow, small, thin, smooth and round; embryo curved inward (on section)
• Pungent smell and taste
• Active principles: Capsaicin and Capsicin (acrid, volatile, non-alkaloidal, non-fatal substances)
• Differ from Dhatura seeds: chilli seeds are smaller, paler, smooth vs. dhatura seeds which are larger, brown/black, kidney-shaped, pitted, and reticulated

• Vegetable/organic irritant poison; non-fatal irritant (NOT a lethal poison in ordinary doses)

• No established fatal dose - considered non-fatal in ordinary quantities

• Not applicable (not typically fatal)

1. Powder used as a means of torture to extort money or confession - introduced into nostrils, eyes, urethra, vagina, or rectum; constitutes assault and torture in law
2. Chilli bomb (pepper spray) used by police for crowd/mob control - regulated use by law enforcement

1. Universal condiment (red pepper/lalmirch) in food
2. Used in superstitious practices to scare away evil spirits; burnt to irritate aggressors

• Skin: Irritation, vesication (blistering)
• Eyes: Burning, lachrymation (tearing), redness, intense pain
• Ingestion: Burning sensation from mouth to oesophagus and stomach; irritant gastroenteritis
• Inhalation (fumes): Irritation of eyes and upper respiratory passages

• Capsaicin selectively binds to TRPV1 (Transient Receptor Potential Vanilloid 1) receptors on sensory neurons (C and Aδ fibres)
• TRPV1 activation causes massive influx of Ca²+ and Na+ - intense burning pain sensation
• Depletes substance P from sensory nerve terminals (initially causes pain, then desensitization/analgesia with repeated use)
• Direct membrane irritant on mucous membranes at high concentrations

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8. DHATURA SEEDS (Datura stramonium / Thorn Apple / Jimsonweed)

• Seeds: brownish to black, kidney-shaped, finely pitted and reticulated; embryo curved outward (on section); bitter taste; odourless; larger and thicker than chilli seeds
• Fruit: greenish-grey, apple-shaped with thorny projections ("Thorn Apple")
• All parts of plant are poisonous; seeds contain maximum concentration of active principles
• Active principles: (1) Hyoscine (Scopolamine), (2) Hyoscyamine, (3) Atropine (anticholinergic alkaloids)

• Vegetable/organic deliriant/cerebral poison; anticholinergic alkaloid

• 50-100 crushed seeds (if ingested)

• 1-2 days if untreated

1. Widely used as a stupefying agent for criminal purposes (robbery, rape, kidnapping) - crushed seeds mixed with sweet food or pan-beedi given deceitfully; person commits acts they don't recall - important in law
2. Used to dope cigarettes or cannabis - forensic detection of hyoscine/hyoscyamine in urine/blood/stomach contents is medico-legal evidence

1. Used by Himalayan Sadhus/ascetics as a psychoactive/religious substance for ages
2. Hyoscine (scopolamine) is used medically as anti-emetic, for motion sickness, and as pre-anaesthetic medication

• Hot as a hare - dry, hot skin (anhidrosis + fever)
• Blind as a bat - mydriasis (dilated pupils), blurred vision, diplopia; conjunctiva red
• Red as a beet - flushed face (cutaneous vasodilation)
• Dry as a bone - dryness of mouth, xerostomia, dysphagia; dry skin
• Mad as a hatter - delirium, hallucinations, agitation, restlessness, picking at imaginary objects, tries to run/jump, homicidal tendencies
• Additional: nausea and vomiting, drunken gait, tachycardia, urinary retention, painful urination
• Stupefaction/amnesia - person does not remember events
• Convulsions followed by coma and death from respiratory arrest if untreated

• Hyoscyamine/Atropine/Hyoscine are competitive muscarinic acetylcholine receptor (mAChR) antagonists
• Block all muscarinic effects of acetylcholine: smooth muscle relaxation (GI, urinary), decreased secretions (saliva, sweat, bronchial), tachycardia, mydriasis
• Hyoscine additionally has CNS activity: causes delirium, hallucinations, amnesia (crosses blood-brain barrier more readily than atropine)
• Antidote: Physostigmine (cholinesterase inhibitor) - 1-2 mg IV slowly, every 5 minutes until signs disappear

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9. GANJA (Cannabis / Cannabis indica / Indian Hemp)

• Ganja: resinous mass made from flowering tops of female Cannabis plant, specially grown for maximal resinous exudate; contains ~1-2% (some sources 25%) THC; rusty green colour with characteristic odour; smoked in pipe (chillum) or beedi
• Active principle: Tetrahydrocannabinol (THC) (delta-9-THC) - fat soluble
• Other preparations: Bhang (dried leaves, 15% THC, least potent), Majun (sweetmeat made with bhang), Charas/Hashish (resinous exudate from leaves/stems, 25-40% THC, most potent)
• Cystolith test: microscopic identification; crystals appear like elephant tusk/bear claw; add 10% chloral hydrate, then 20% HCl - CO2 bubbles (effervescence)

• Vegetable/organic cerebral deliriant; hallucinogen; narcotic/psychoactive

• No scientifically authenticated fatal dose
• Some authors mention: IV cannabis ~1-2 g; oral ~700 g as potentially fatal
• Lethal dose of ganja: ~8 g/kg body weight (Parikh); charas ~2 g/kg; bhang ~10 g/kg

• ~12 hours in acute poisoning

1. Used as a stupefying poison (majun/charas) prior to robbery, kidnapping, and rape - mixed in food/beverages; constitutes criminal use under NDPS Act (India)
2. THC detected in urine (50-100 ng%) up to 7-8 weeks after use - important in forensic drug testing; positive urine THC is admissible legal evidence; also used to detect doped cigarettes

1. Sadhus and temple priests use it to achieve religious fervour/spiritual states
2. Medically: THC (dronabinol) approved for chemotherapy-induced nausea, appetite stimulation in AIDS wasting syndrome

• Acute (triphasic pattern):
  • Phase 1: Euphoria, relaxation, garrulity, hilarity; colours appear brighter, sounds clearer
  • Phase 2: Philosophical thinking, introspection, hallucinations, sedation, increased appetite, conjunctival congestion (characteristic red eyes)
  • Phase 3: Tachycardia, palpitation, hypotension, rhinitis, cough, bronchitis; convulsions and cardiac arrest (overdose)
• Chronic:
  • Cannabis psychosis (manic, schizophreniform, confessional psychosis)
  • Amotivational syndrome: apathy, poor concentration, social withdrawal
  • Cyclical hyperemesis syndrome
  • Suicidal/homicidal tendencies, accidents
  • Chronic lung disease, cancers of mouth and larynx, aspergillosis, clubbing of digits
  • Hashish insanity: delusions of grandeur or persecution
  • "Running amok" - frenzied desire to commit murders

1. THC acts on CB1 receptors (endocannabinoid system) in the CNS (hippocampus, cortex, cerebellum, basal ganglia) and CB2 receptors (peripheral tissues)
2. Mimics/modulates endogenous neurotransmitters: GABA, dopamine, acetylcholine, histamine, serotonin, noradrenaline, and prostaglandins
3. Small doses: CNS excitation; large doses: CNS depression
4. Being fat-soluble, THC is stored in fat cells - acts as a time-release capsule; effects of single dose last >7 days
5. Smoking produces immediate effects; oral consumption produces slow, unpredictable effects
6. Inhibits adenylate cyclase via Gi-protein coupling

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• Colour-coded card with its own unique theme colour (steel blue, poison green, crimson, amber, orange, purple, red, teal, earthy green)
• Active principle named prominently
• Fatal dose + fatal period with coloured badges
• Key molecular/receptor target highlighted
• Mechanism of action (step-by-step)
• Clinical features sorted by system/severity (danger/warning/info tags)
• Antidote + judicial + non-judicial uses in the footer

• Dark forensic theme (professional and print-ready)
• Danger badges (red = fatal, orange = warning, green = safe/non-fatal)
• "TRPV1" target for capsicum, "mAChR antagonist" for dhatura, "Type II RIP" for ricin/abrin - all mechanistically precise
• Classic anticholinergic toxidrome for dhatura displayed as the 5 mnemonics (Hot/Blind/Red/Dry/Mad)

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• Judicial use patterns across all 9 (homicide types, torture, abortion, bioterrorism)
• Non-judicial use patterns (industrial, folk, ritual, pharmaceutical)
• Medico-legal significance patterns (DFSA, exhumation, criminal insanity, mandatory reporting)