What was the best commodity introduced to the new world by the columbian exchange? what was the worst?

Christopher Colombus introduced to the New World horses, sugar and plants. Of all of these commodities, sugar proved to be the most important one. Although refined sugar was available in the Old World, Europe's harsher climate made sugar cane difficult to grow. Colombus brought sugar in 1943 and the crop prosper. Caribbean islands and most other tropical areas became centers of sugar production.

On the other hand, the Old World diseases had a devastating effect when introduced to Native Americans via European carriers, as the people in America had no natural immunity to new diseases. Measles caused many deaths. The smallpox epidemics are believed to have caused the largest death tolls among Native Americans. Yellow fever is thought to have been brought to the Americas via the Atlantic slave trade. The disease caused widespread fatalities in the Caribbean during the bloom of slave-based sugar plantations. That been said, diseases were the worst commodity brought into the New World.