Aspirin, also known as acetylsalicylic acid, is the oldest analgesic on the market. Aspirin is an NSAID (nonsteroidal anti-inflammatory drug). Because of its anti-inflammatory properties, it is often used to treat arthritis, toothaches, and other pains aggravated by inflammation. It is also used to treat minor body aches and pains, headaches, and reduce fevers. Aspirin has two major side effects. The first is that it can be stomach irritant. In fact, it can irritate any tissue it comes into contact with (thus chewing aspirin gum is not recommended because it can irritate the gums and mouth). Also, people who know they are allergic to salicylic acids in general are urged to avoid aspirin. But many who take aspirin, even on a regular basis, do not have stomach irritation.

You may be wondering why some people take aspirin regularly. Another big “side effect” of aspirin can actually be a benefit for many people. Aspirin thins out platelets, the cells responsible for blood clots. While clotting helps stop bleeding when you cut yourself, clots also play a big role in causing strokes and heart attacks when blood vessels are already partially blocked by cholesterol. Fewer platelets means smaller chance of heart attack or stroke, so health care providers often prescribe aspirin for this.

Ibuprofen (commonly branded as Advil or Motrin) is one of the newest analgesics, approved by the FDA in 1974. It may have some advantages over aspirin, depending on the type of pain you are experiencing. It appears to be slightly stronger (meaning you need less of it) to treat pain from soft tissue injuries and dental pain. In addition, it has been shown to be the most effective pain reliever for menstrual pains. In fact, here’s a tip: all of the pain relievers marketed exclusively for this purpose (e.g. Midol) contain ibuprofen, but they cost much more because they are marketed as a “high tech” pain reliever. Stick with generic ibuprofen for menstrual cramps. Ibuprofen can also be a stomach irritant, but this occurs much less commonly than with aspirin. Unlike aspirin, it has a very mild blood-thinning effect, so if you have conditions where loss of platelets would be a concern, ibuprofen is a better choice. There have been some concerns that ibuprofen can contribute to kidney damage, so those with kidney concerns should consult with a health care provider before taking it.

Acetaminophen (also known as paracetamol, and commonly branded as Tylenol or Excedrin) was introduced in 1955. It has about the same pain-relieving power as aspirin for pains not caused by inflammation, but is slightly less effective for inflammatory pain. This is because it doesn’t alleviate inflammation, and is probably not as effective with menstrual cramps as ibuprofen. Of all the analgesics, acetaminophen is the least likely to be a stomach irritant. However, taking more than 325mg of acetaminophen at a time, taking more than one type of medication that contains acetaminophen, or taking it with alcohol can lead to severe liver damage — which can require a liver transplant or even result in death.

Naproxen (Aleve) is another NSAID. It didn’t become available without a prescription in the U.S. until 1994. It is the most powerful pain reliever currently available without a prescription, but can cause even more gastrointestinal irritation than aspirin. As a result, it needs to be taken in fewer doses, and with lots of water.

Regardless of what pain reliever you might choose or is most appropriate,remember to follow the directions on the label — just like you would with prescription medications. Hopefully this helps clear up some of the confusion. You may want to check out the related Q&As for more info about analgesics.