Also known as hippie crack, and widely available at head shops. Nitrous oxide falls into an interesting gray zone of legality due to its use as a whipped cream propellant. Most states have laws against the intoxicant use of nitrous oxide while otherwise leaving it legal.

Nitrous oxide can be damaging or fatal if abused. The most common problem is method of use. If obtained from a whippet, nitrous comes out very cold, and people have injured themselves by putting the cracker in their mouth or so what. Be careful with pressurised tanks - unregulated pressure can damage your lungs. Never put on a mask of nitrous - people have died when they've lost consciousness and suffocated on the mask. The nitrous oxide used in a medical situation is mixed with oxygen and therefore safe. Never use the nitrous oxide available for race cars - it's mixed with other chemicals such as sulfur gas that will seriously damage your lungs. Nitrous oxide is not widely thought of as a physically addictive drug, but some cases of physical dependence have been reported. If used repeatedly, nitrous oxide will attack nerves in your extremities . Vitamin B12 supplements apparently ward off damage. Heavy nitrous use (300-400 times a week for several months) has sent people to the hospital without sensation in their limbs.