Anything used not in moderation can have bad side effects. All side effects are listed on products, by law, even if the occurrence is rare. Two different doctors recently suggested I use Voltaren, one is a tennis friend who is a primary physician and she uses it regularly on her joints, and the other I saw 2 weeks ago, an orthopedist, suggested it too for my wrists pain, etc. He told me that active ingredient is the SAME as in Aleve, but less potent, because we ingest Aleve into our blood, but only rub Voltaren on our skin, so it is less powerful, less invasive, but you have to use it as instructed, a least a few times a day for it to be effective. I choose to reserve Aleve, or other similar pain inflammation reducing pills, for when I am really in pain, and for moderate aches, etc..I am using less potent, less invasive Voltaren...I do feel it helps...but every body is different..I also exercise regularly, stretch, to yoga, drink lots of water, eat healthy, and all of those things impact inflammation prevention as well.