of kratom. An analytical method using whole genome sequencing applied to samples from the infected users indicated that the salmonella outbreak likely had a common kratom source. Addiction Kratom is a botanical with a known addiction liability and, in vulnerable individuals, dependence may develop rather quickly with tolerance noted at 3 months and 4- to 10-fold dose escalations required within the first few weeks. Kratom addiction carries a relapse risk as high as 78% to 89% at 3 months post-cessation. In cases of severe addiction, a similar approach to treatment of opioid addiction may be warranted. Respiratory depression Respiratory depression is the leading cause of death from opioid use. Although evidence is sparse, the risk of respiratory depression caused by taking Mitragyna speciosa appears to be low, but the Food and Drug Administration listed respiratory depression as a concern. Confusingly, a 2018 review found that the alkaloids in kratom do not induce respiratory depression. Liver toxicity In rare cases, though with a dangerous delay, kratom use has been linked to acute liver injury, with symptoms of abdominal discomfort, dark urine, itching and jaundice. Liver injury has been reported with a latency (time from first use to onset of symptoms) of median 20.6 days. Reported liver biopsies tend to show cholestasis; however, blood biomarkers can show a range of cholestatic, mixed, or hepatocellular injury pattern. The majority of users do not seem to develop liver injury, and it is unclear which users are at heightened risk. The mechanism by which kratom causes liver damage in some people is unknown and poorly studied, but a model has been proposed. Death Kratom overdose is a subject of concern in many countries because of the associated rising number of hospitalizations and deaths in which chronic kratom use is a contributing factor. According to clinical reviews, a kratom overdose can cause liver toxicity, seizures, coma, and death, especially in combination with excessive alcohol use. Between 2011 and 2017, 44 U.S. deaths were kratom-related. However, many cases could not be fully assessed, due to limited information. People who die from kratom use typically have taken it in combination with other substances, or have underlying health conditions. Over 18 months in 2016 and 2017, 152 overdose deaths involving kratom were reported in the United States, with kratom as the primary overdose agent in 91 of the deaths, and 7 with kratom being the only agent detected. Nine