That wonderful and often misspelled ingredient in the tasty chemical stew of NyQuil. Pronounced Sue Doe Eff Ed Rin, this stuff is at the same time a stimulant and a decongestant. When consumed with the depressant drugs in NyQuil, a strange, sometimes hash-ish buzz is resultant.

This stimulant quality of this dope is what earns it a ban from most professional sports.

Some side effects of pseudoephedrine are as follows:
dry mouth, insomia, nervousness, nausea, loss of appetite, vertigo.

Don't take too much of this shit, I read a couple of studies that make it sound like heavy use is as bad as snorting coke:
"Pseudoephedrine, like other central nervous system stimulants, has been abused. At high doses subjects commonly experience an elevation of mood, a sense of increased energy and alertness, and decreased appetite. Some individuals become anxious, irritable, and loquacious. In addition to the marked euphoria the user experiences a sense of markedly enhanced physical strength and mental capacity. With continued use, tolerance develops, the user increases the dose, and toxic signs and symptoms appear. Depression may follow rapid withdrawal."

so take it easy on this shit