A few LD50 ([Lethal] [dose] for 50% of the population studied) values:
[Alcohol] ([Ethyl Alcohol]): 10.6 g/kg, [young rats], [orally]
[Antifreeze] ([ethylene glycol]) 6.86 g/kg, [rats], [orally]
[Table salt] ([sodium chloride]) 3.75 g/kg, [rats], [orally]
[Marijuana] ([THC|delta1-3,4-trans-tetrahydrocannabinol]) 3.75 g/kg, [rats], [orally]
[GHB] (Gamma-Hydroxybutyrate, as [sodium]-GHB) 2 g/kg, [rats], [intraperitoneal]
[Wormwood] ([thujone], one of the main [constituent] of [absinth]) 0.45 g/kg, [mice], [orally]
[Chocolate] ([theobromine] by itself, although chocolate also [contains] [caffeine]) 0.310 g/kg, [rats], [orally] (much higher for cats and dogs)
[Ketamine] (2-(2-Chlorophenyl)-2-(methylamino)cyclohexanone) 0.229 g/kg, [rats], [orally]
[Ecstasy] ([MDMA]): 0.049 g/kg, [rats], [intra peritoneal]
[Psychoactive Amanitas] ([Muscimol]): 0.045 g/kg, [rats], [orally]
[LSD-25] ([lysergic acid diethylamide]): 0.0165 g/kg, [rats], [intravenous]
[Strychnos] [seeds] ([brucine]) 0.001 g/kg, [rats], [orally]
[Nicotine] (3-(1-methyl-2-pyrrolidinyl)pyridine) 0.0003 g/kg, [mice], [orally]
[Ricin] (a [high molecular weight protein] made from [castor beans], it has been used in [experimental treatments] for [cancer] and [AIDS]) 0.000005 g/kg, [mice], [orally]
[Enya] ([new age] female [Celtic bard]): 0.0 g/kg ([instant death]), rats and [human] alike, [aurally]
(compiled from miscellaneous sources, including [Erowid] and the Registry of Toxic Effects of Chemical Substances (RTECS)...
A few comments and personal conclusions from this list:
You should not drink antifreeze.
You should not try to [assess the accuracy] of these [data] by trying with your [dog]/[cat]/[goldfish]/[neighbourhood] [rat] [population]/[significant other]/[kids]. Unless you are scientifically qualified to conduct this [type of experiment].
From looking at this list, it should be pretty obvious that LD50 values are to be taken with a [huge grain of salt] (although no more than 3.75 g/kg if you are an [adult-size] [lab rat]): I think we all know that chances to die from a [GHB overdose] are much higher than from a [chocolate overdose], despite appearances of the contrary. The [nuance] between [toxicity] and [lethality] plays a large role in these discrepancies, as well as the essential difference in [metabolism] between a small [rodent] (known for thriving amidst major city's most [sewers|toxic areas]) and a much larger [biped] (also known for thriving in said cities, right next to said [toxic areas], but that's not a reason).
Despite my best efforts to [harmonize] the data (trying to pick preferably [oral administration] on [male] [adult] [rats]), I was not always able to find perfectly matching data due to [lack of source] or nature of substance involved ([rats will eat about anything], but there is a limit).
Although LD50 experiments altogether are a much [controversial issue], due to its particularly [inhuman and cruel] aspect, the use of [Enya]'s music should decently be [ban]ned from any [self-respecting] scientist's [laboratory].