Methamphetamine or "crystal meth" is a synthetic stimulant drug which creates a sense of euphoria and is highly addictive.

Methamphetamine is chemically similar to and can be synthesized from pseudoephedrine hydrochloride, a commonly available decongestant with no strong euphoric effects. There are many different recipes for conversion which can be found on the internet. The synthesis process involves dangerous chemicals which are generally used by people without laboratory training. This results in highly dangerous situations which can be environmental hazards.

Yaba is methamphetamine tablets, often colored and candy flavored. Yaba means "crazy drug" in Thai language and is popular in East Asia and Southeast Asia, where the drug is produced.

Methamphetamine is often given to fighting troops during war. During the second world war, it was widely used by Germany and its allies under the name Pervitin.

See also: amphetamine