(from erowid.org)

Psychoactive LD50s

LD50 - The dose that has been determined to be lethal to 50% of the test population.

LD50s for Various Substances
(with ratios regarding relative safety/toxicity)
Substance	LD50	route	animal	Typical Human Dose
Alcohol (Ethyl)	10.6 g/kg	o	young rats
	7.06 g/kg	o	old rats
AMT	38 mg/kg3	ip	mouse
	22 mg/kg3	o	rat
Caffeine	127 mg/Kg	o	mice (male)	100-200mg o
	192 mg/Kg	o	rat
	260 mg/Kg	ip	rat
	105 mg/Kg	iv	rat
	137 mg/Kg	o	mice (female)
	230 mg/Kg	o	hamster(male)
	249 mg/Kg	o	hamster(female)
	355 mg/Kg	o	rat(male)
	247 mg/Kg	o	rat(female)
	246 mg/Kg	o	rabbit(male)
	227 mg/Kg	o	rabbit(female)
	140 mg/Kg	o	dog
Cocaine	95.1 mg/kg4	ip	mouse
DET	28 mg/kg	iv	mouse	60 mg im/po
DIPT	26 mg/kg	iv	mouse	30 mg o
DMT	110 mg/kg	im	mouse	60 mg im
5-MeO-DMT	115 mg/kg	ip	mouse	6 mg p
DPT	20 mg/kg	iv	mouse	60 mg po
Sodium-GHB	2,000 mg/kg	ip	male rats
	1,650 mg/kg	ip	female rats
Ibogaine	82 mg/kg2	ip	guinea pig
	145 mg/kg2	ip	rat
Ketamine	77 mg/kg	iv	mouse
	400 mg / kg	ip	mouse
LSD	46 mg/Kg	iv	mice	0.25 mg o
	16.5 mg/Kg	iv	rats
	.3 mg/Kg	iv	rabbits
MDA	92 mg/kg5	ip	mouse
MDMA	350 mg/kg5	oral	rats
	106 mg/kg5	ip	mouse
Mescaline	370 mg/kg	o	rats
Nicotine	230 mg/Kg	o	mice
	50 mg/Kg	o	rats
	9.5 mg/Kg	ip	mice	.7mg(smoked)
	.3 mg/Kg	iv	mice
Psilocybin	285 mg/Kg	iv	mice	12-20 mg o
	280 mg/Kg	iv	rats
	12.5 mg/Kg	iv	rabbit
THC	1270 mg/Kg	o	rats(male)	20mg o
	730 mg/Kg	o	rats(female)	20mg o
	105.7 mg/Kg	iv	rats	5mg(smoked)
	42 mg/Kg	(inhalation)	rats	5mg(smoked)
Aspirin	1100 mg/Kg	o	mice	325mg o
	1500 mg/Kg	o	rats
Acetaminophen	338 mg/Kg	o	mice	500mg o
	500 mg/Kg	ip	mice
Vitamin A	2570 mg/Kg	o	mice	10-20mg o
	1510 mg/Kg	ip	mice
Strychnine	.96 mg/Kg	iv	rats
Succinyl Choline	.45 mg/Kg	iv
VX (nerve gas)	.0154 mg/Kg	iv	rabbits	0 mg

Abbreviations:

iv = intravenous (injected into vein)
ip = intraperitoneal (injected into body cavity)
im = intramuscular (injected into muscles)
o=oral (swallowed or eaten)
p=parenteral (not by mouth / usually means 'inhaled' or 'snorted')
mg/Kg = milligrams of drug per Kilogram of body weight
mg = milligrams of drug


Example acute oral LD50s (rat): Example LD50 (mg/kg) Citric acid (solid) 3,000 10% Citric acid Soln. 30,000 Acetone 5,800 Benzoic acid 1,700 Caffeine 192

---

NOTES:

The "LD50" is the dose of a substance that will kill a selected species of experimental animal 50% of the time.

All LD50's are normalized to milligrams/Kilogram of animal's body weight.

"Typical Human Dose" info is taken from various sources, including "Burger's Medicinal Chemistry", "Journal of Psychedelic Drugs", "The Merck Manual", "NIOSH Registry of Toxic Effects of Chemical Substances", cigarette packages, No-Doz bottles, etc.

One might well argue that it is of questionable utility to compare toxic responses between various species using different routes of administration. Needless to say, many rodents have died for our sins.

It was later pointed out that what is called above a "safety ratio" is roughly equivalent to the pharmacological measure known as the "Therapeutic Index". The therapeutic index is a measure of the toxicity of a drug relative to it's usual therapeutic dose.

The NIOSH Registry of Toxic Effects of Chemical Substances also lists most published LD50 measurements, but does so uncritically. It's quite useful as a point of reference.

REFERENCES:

1. Unless otherwise marked, all LD50 data were found in the "The Merck Index, 11th edition".
   
   
2. Goutarel R, Gollnhofer O, Sillans R. "Pharmacodynamics and Therapeutic Applications of Iboga and Ibogaine." Psychedelic Monographs and Essays #6. Ed. Thomas Little. Pompano Beach: PM & E Publishing Group, 1993. 70-111.
   
   
3. Toxicol. Appl. Pharmacol. 4, 547 (1962)
   
   
4. Bedford JA, Turner CE, Elsohly HN. "Comparative lethality of coca and cocaine." Pharmacol Biochem Behav 1982 Nov; 17(5):1087-8
   
   
5. U.S. Dept of Justice - DEA. MDMA Scheduling Hearings with Francis L. Young, Administrative Law Judge