Ibuprofen is an
analgesic drug, that is very good for relieveing
fevers,
headaches, and overall
achiness.
Ketoprofen is a similar, but more potent, drug in the same family of drugs.
Other analgesics include aspirin, acetaminophen (trade name Tylenol), and naproxen sodium (trade name Aleve).
I personally favor ibuprofen over the other drugs, though a combination of ibuprofen and aspirin can be highly effective.
For children, ibuprofen or tylenol are the only real choices, as aspirin can cause Reye's Syndrome, a potentially fatal disease.
Ibuprofen is also sometimes called Vitamin I and (in the SCA) "fighter candy."