It's the "active" ingredient in most cold medicine. There's real Sudafed behind the counter, and everything else is just varying amounts of phenylephrine, aceta

It's the "active" ingredient in most cold medicine. There's real Sudafed behind the counter, and everything else is just varying amounts of phenylephrine, acetaminophen, guaifenesin, and dextromethorphan. If you read labels for otc medication, you see these same names over and over again.