The gold standard was a system whereby national currencies were based upon the price of gold. Various problems arose from this and it was abandoned by most governments by World War II. The final blow came when the United States abandoned it and most of the Bretton Woods Agreements in 1973.
The gold standard did work to keep prices largely stable over long periods of time. In this respect it helped prevent inflation, but there were also problems with it.
Money is a commodity like any other. The supply can fall short of what is needed. This is especially true of using gold as money. When trade between different nations or regions takes place it is often uneven. This means that gold will flow from places importing more than they export. This leads to a lack of currency and an economic slow down. In theory this should self correct the problem of gold outflows by making goods from elsewhere more expensive relative to locally produced ones. The main problem with this is that economies are high viscosity systems. Changes now take quite a while before they change economic activity. So the gold outflows continue long after a point that would be healthy and result in bank collapses and financial panic.
The second problem is related to the first. National governments recognized that insufficient currency for economic activity was a bad thing. Therefore they sought to keep the national currency strong to bolster confidence (preventing outflows) and as a matter of national pride. This usually only makes the problem worse. A great example of this policy at work was the Great Depression in the United States. To stop gold outflows and support the gold standard, interest rates were raised by the Federal Reserve. This helped slow the flight of gold, but resulted in even less money being loaned by banks and an exacerbation of the recession into a general depression that spread worldwide.
An additional problem is that the money supply contracts and expands somewhat randomly when gold is used as currency. The production of gold is in private hands and dependant upon discovery of new sources. Using the gold standard today would make South Africa the producer of 39.1% of the world’s currency and give that nation a control over the world economy unmatched even by OPEC. (Note the next largest producer, the US only had 9.3% of the world's gold ore reserves.)
Lastly there has never been enough gold to go around. People do not value gold highly enough (the price is often below $300 per troy ounce today) for the current world supply of gold to be used as currency. In the past this has meant large amounts of the world were on the barter system before paper money started to be used to represent some amount of precious metal.
Generally economists agree that a gold standard is inferior to fiat currency backed by a central banking system.