Ibuprofen is in a class of drugs called NSAIDs (Non-Steroidal Anti-Inflammatory Drugs). The acronym gives one a clue about how they work. Ibuprofen, like aspirin, reduces inflammation. The expansion and irritation of tissue generates nerve signals that we perceive as pain. Reducing the inflammation reduces the pain.

Also like aspirin, ibuprofen is used to treat a wide variety of conditions - arthritis, abdominal cramps from menstruation and many others. But, like aspirin, it can produce side effects. Blood in vomit or stools, general stomach upset even dizziness are commonly reported.

Other potential side effects include allergic reactions, leading to swelling of the throat or tongue, fluid retention and ringing in the ears. Since it works by changing blood composition, as does aspirin, anyone who has had heart surgery should avoid it.

Those with a liver or kidney disease, too, should consult a doctor before taking ibuprofen. Patients with ulcers or those taking coagulation medication should as well. Anyone with high blood pressure or heart disease should find a substitute. Nausea is fairly common and diarrhea is sometimes reported.

Ibuprofen is not suitable for pregnant women though it's generally safe during early stages. It is particularly risky in the last trimester, as it may produce birth defects. The compound in ibuprofen can be passed through the blood stream into the fetus. Consulting a physician is a wise precaution.

All these side effects can be minimized by proper dosage and consumption. If taken in liquid form, use a carefully calibrated measuring spoon or small cup, rather than a teaspoon. Alcohol shouldn't be consumed with or just before hand, and the ibuprofen should be taken with a glass of milk or water.

In general, it shouldn't be combined with other over-the-counter pain medications, such as aspirin or naproxen. The list of other drugs that can interact unfavorably is, not surprisingly, very long. Some of the more common ones are steroids (prednisone, for example), lithium (such as Lithobid) and diuretics.

On the upside, ibuprofen has been shown to be very effective in treating a wide variety of headaches. Some, such as those produced by high altitudes (a condition called AMS ñ acute mountain sickness) respond very well to ibuprofen. That's good news for climbers and those who travel in planes frequently.

Studies differ on which is more effective for treating headaches, ibuprofen versus aspirin or acetaminophen. In the end, it often comes down to a personal decision based on individual effects. To judge that, look for side effects from ibuprofen and - most importantly - whether your headache goes away.