Answer:
Pseudoephedrine or ephedrine
Step-by-step explanation:
The core ingredient of methamphetamine is pseudoephedrine or ephedrine, both of which are common decongestants found in over-the-counter cold and allergy medicines. Methamphetamine is a highly addictive central nervous system stimulant drug that affects the brain's reward and pleasure centers. Methamphetamine can be made using a variety of ingredients and methods, but the use of pseudoephedrine or ephedrine is most common in illegal meth production because these chemicals are readily available and relatively inexpensive. The production and use of methamphetamine is illegal in most countries due to its highly addictive nature and the negative health effects it can have on users.