GENESEE COUNTY, MI — Flint health and drug rehabilitation officials say they are treating a growing number of patients using what they call a “gas station opioid” — a highly concentrated byproduct of kratom that’s being sold at convenience stores and smoke shops throughout Genesee County.

While 7-Hydroxymitragynine occurs naturally in trace amounts of kratom — pills, energy drinks and candy being sold as 7-OH are super-concentrated and can be more potent than opioids like morphine.