Coca growers faced off with police in Bolivia's capital La Paz on Monday as they battle for control of coca's main market.
Rocks were thrown and tear gas fired.
Thousands travelled from the Los Yungas region, in the west, to the Bolivian capital to protest leadership in a regional coca growers association.
There are two factions of farmers in this fight,one who supports government critic Armin Lluta who says the ruling party and former president Evo Morales is trying to seize greater control of the trade.
And the other other, the government-backed head of the coca management body Adepcoca, Arnold Alanes:
"We demand that a resolution has to be passed to enable and make viable the transfer of a commercial market to a new site for coca growers."
Coca, the raw ingredient for cocaine is chewed by many in the Andes to ward off the effects of high altitude or is brewed in teas.
Coca farmers have pointed towards tough conditions for stoking the unrest.
Others have called for dialog with the government, and installing a new head of the coca management body.
The Yungas region produces and trades some $200 million of coca a year in the local market, according to estimates by the U.N. Office on Drugs and Crime.