People prescribe to pain-reducing and anti-inflammatory drugs like NSAIDs and COX-2 Inhibitors without knowing correctly the specifications of each, what the difference between each is, and what would be better for each particular case.

COX-1 is the name of a certain enzyme which is usually most prevalent in the sites where the tissues have gotten inflamed. This is the enzyme which is responsible for producing the hormone known as prostaglandin that is responsible for causing swelling and inflammations. These hormones also act as a protective layer over the internal walls of the stomach.  Thus NSAIDs which block this can cause digestive problems as a side-effect. Nausea, flatulence, even ulcers and internal bleeding are common side-effects.  

On the other hand, COX-2 inhibitors block the production of the hormone prostaglandin by barring the COX-2 enzyme to have any effect on the activation of the hormone. However, when comparing the COX-2 enzyme to the COX- enzyme, one would notice that the COX-2 enzyme has no effect on the stomach whatsoever, and does not act as a protective agent over the stomach liming like COX-1 does. Thus the intake of COX-2 inhibitors over NSAIDs will result in less intestinal problems.