Large amounts of PCP may cause convulsions, coma, hyperthermia, and death.
Moldy or bad magic mushrooms may contain poisons and harmful bacteria that can make a person very ill.
Inhaling propane to get high, a substance found in lighter fluid and hair spray, can cause sudden sniffing death syndrome due to the cardiac effects and serious burn injuries due to the flammability factor.
Many doctors in the U.S. choose to use methadone for treating chronic pain in patients even though some of these patients are thought to have a propensity for addiction.