Opioid crisis: US pharmacies face moment of truth as trial begins

Walgreens Boots Alliance, CVS, Walmart and Giant Eagle deny failing to stop excessive amounts of addictive prescription painkillers being sold in two Ohio counties.

If found liable, they could face a wave of litigation and billions of dollars in compensation - not to mention serious reputational damage.

More than 3,300 similar cases have been brought, largely by US state and local governments.