Many athletes take ibuprofen before working out to prevent muscle soreness and increase the duration/intensity of their workout. Non-steroidal anti-inflammatory drugs (NSAIDS) like Advil or Motrin, sound like a good idea at first. No pain so I can gain, right? Right? Wrong.
Researchers in the Netherlands measured the blood levels of nine males on a stationary bike. They found that when taking an NSAID, the riders had an 84% increase of a protein in their bloodstream indicative of intestinal damage. Strenuous exercise paired with the loss of intestinal lining can ultimately lead to ulcers or GI bleeding. Some stress on the body is a good thing but the combination of both NSAID medicines and exercise at once hurts the body more than helping it. Some studies not only show intestinal damage, but kidney damage as well.
Research has also shown that NSAIDs can disrupt the production of collagen. Collagen is a key component to your muscles, tissues, tendons, and bones. Thus taking something like Advil before your workout can actually decrease the benefits of exercise, by increasing musculoskeletal injury and delaying recovery.
Unless you're taking an NSAID because you have arthritis or something that prevents you from working out otherwise, try to avoid popping one before your next workout. Instead, try stretching to warm up the muscles and joints to prepare them for your routine.
References:
http://www.menshealth.com/fitness/ibuprofen-intestinal-damage
http://www.quickanddirtytips.com/health-fitness/exercise/should-you-take-ibuprofen-before-exercise?page=all