Nauru [wiki] is the world's smallest island nation, the smallest independent republic, and the only republic in the world without an official capital. Nauru only has one significant source of income: phosphates from thousands of years' worth of guano or bird droppings.
We may have the same friends. The same ones who take NyQuil when they're not really sick, just to help them sleep. So they're taking it for the diphenhydramine (Benadryl), which is much more cheaply purchased alone and as a generic. DayQuil is dextromethorphan, acetaminophen, and phenylephrine.
Vicks DayQuil Severe Cold-Flu. One ingredient in this product is acetaminophen. Taking too much acetaminophen may cause serious (possibly fatal) liver disease. Adults should not take more than 4000 milligrams (4 grams) of acetaminophen a day. People with liver problems and children should take less acetaminophen. Ask your doctor or pharmacist how much acetaminophen is safe to take.