Complex sentence: In its natural form, kratom appears to be relatively safe, and while dependence on its opioid effects is known to occur with frequent use, serious respiratory depression and life-threatening adverse events are undocumented.
Split into simpler sentences: In its natural form, kratom appears to be relatively safe. While dependence to its opioid effects is known to occur with frequent use, serious respiratory depression and life-threatening adverse events are undocumented.