What were the positive and negative effects of European exploration?

The positive effects were that the explorers gained wealth and fame; they were able to bring back new items to their home country; they were able to bring back large quantities of spices, silver, etc.; and new trade routes were developed.

The negative effects were that explorers were at risk of death; if the trip failed a lot of money would be wasted; and there were risks that the explorers could bring diseases back to their home countries.