Let's start off with stating that any and all substances can
kill you (even too much water), whether they be legal or not. Since
you ask which illegal drugs can kill you, the answer would be ALL
illegal drugs. The following is an attempt list of all controlled
substances:
((+/-)cis-4,5-dihydro-4-methyl-5-phenyl-2-oxazolamine)
(+/-)cis-4-methylaminorex
1-[1-(2-thienyl)cyclohexyl]
1-phenylcyclohexylamine
1-piperidinocyclohexanecarbonitrile
2,5-dimethoxy-4-ethylamphet-amine
3,4,5-trimethoxy
3,4-methylenedioxy-N-ethylamphetamine
3,4-methylenedioxymethamphetamine
3-Methylfentanyl
3-methylthiofentanyl
4-Bromo-2,5-dimethoxyphenethylamine
4-methoxyamphetamine
4-methyl-2,5-dimethoxy-amphetamine
Acetorphine
Acetyl-alpha-methylfentanyl
Acetyldihydrocodeine
Acetylmethadol
Alfentanil
Allylprodine
Alpha-ethyltryptamine
Alpha-methylfentanyl
Alpha-methylthiofentanyl
Alpha-methyltryptamine
Alphacetylmethadol
Alphameprodine
Alphamethadol
Alphaprodine
Amobarbital
Amphetamine
Anabolic
Anileridine
Benzethidine
Benzphetamine
Benzylmorphine
Beta-hydroxy-3-methylfentanyl
Beta-hydroxyfentanyl
Betacetylmethadol
Betameprodine
Betamethadol
Betaprodine
Bezitramide
Bufotenine
Carfentanil
Cathinone
Chlorhexadol
Chlorphentermine
Clonitazene
Clortermine
Cocaine
Codeine
Codeine-N-Oxide
Cyprenorphine
Desomorphine
Dextromoramide
Diampromide
Diethylthiambutene
Difenoxin
Dihydrocodeine
Dihydroetorphine
Dihydromorphine
Dimenoxadol
Dimepheptanol
Dimethylthiambutene
Dimethyltryptamine
Dioxaphetyl
Diphenoxylate
Dipipanone
Dronabinol
Drotebanol
Ethylamine
Ethylmethylthiambutene
Ethylmorphine
Etonitazene
Etorphine
Etoxeridine
Fentanyl
Furethidine
Glutethimide
Granulated
Heroin
Hydrocodone
Hydromorphinol
Hydromorphone
Hydroxypethidine
Ibogaine
Isomethadone
Ketamine,
Ketobemidone
Levo-alphacetylmethadol
Levomoramide
Levophenacylmorphan
Levorphanol
Lysergic
MPPP
Marihuana
Mecloqualone
Mescaline
Metazocine
Methadone
Methadone-Intermediate
Methamphetamine
Methaqualone
Methcathinone
Methylaminorex
Methyldesorphine
Methyldihydromorphine
Methylphenidate
Methyprylon
Metopon
Moramide-Intermediate
Morpheridine
Morphine
Morphine-N-Oxide
Myrophine
N,N-dimethylamphetamine
N-Benzylpiperazine
N-[1-(2-thienyl)methyl-4-piperidyl]-N-phenylpropanamide
N-[1-benzyl-4-piperidyl]-N-phenylpropanamide
N-ethyl-3-piperidyl
N-ethylamphetamine
N-hydroxy-3,4-methylenedioxyamphetamine
N-methyl-3-piperidyl
Nabilone
Nicocodeine
Nicomorphine
Noracymethadol
Norlevorphanol
Normethadone
Normorphine
Norpipanone
Opium
Oxycodone
Oxymorphone
PEPAP
Para-fluorofentanyl
Parahexyl
Pentobarbital
Pethidine
Pethidine-Intermediate-A
Pethidine-Intermediate-B
Pethidine-Intermediate-C
Phenadoxone
Phenampromide
Phenazocine
Phencyclidine
Phendimetrazine
Phenmetrazine
Phenomorphan
Phenoperidine
Pholcodine
Piminodine
Piritramide
Powdered
Proheptazine
Properidine
Propiram
Psilocybin
Psilocyn
Pyrrolidine
Racemethorphan
Racemoramide
Racemorphan
Remifentanil
Secobarbital
Sufentanil
Sulfondiethylmethane
Sulfonethylmethan
Sulfonmethane
Tetrahydrocannabinols
Thebacon
Thebaine
Thiofentanyl
Thiophene
Tiletamine
Tilidine
Tincture
Trimeperidine
gamma hydroxybutrate
gamma-hydroxybutyric acid
How will they kill you? Given the exhausting list, the simplest
way to answer that is by overdose. Obviously, a drug overdose is
unique to the drug that's causing it. Instead of listing each
drug's mechanism of overdose here, I recommend you find the drug
you're interested in and then look up info on it, including things
like its LD50.
There no known fatal dose of LSD.Cannabis youd have to take so
much youd be sick before you OD'd.Theres never been a recorded case
of LSD or cannabis overdose.