ABSTRACT This is a request for supplement to the R01AA027972 titled “Hybrid trial for alcohol reduction among people with TB and HIV in India (HATHI)”. The proposed study is related to the parent study aim (aim 2) that seeks to examine the effectiveness of alcohol reduction on TB treatment outcomes. In aim 1 of this supplement, we propose to assess whether and how the intervention affects TB drug levels during treatment. Further, as one of the outcomes for aim 2 is TB treatment adherence, we propose to assess adherence through an objective measures (urine INH dipstick) in addition to the subjective questionnaires already being used in HATHI. In aim 2 of the this supplement, we propose to collect blood and stool samples in order to create a biorepository. This will allow for future studies (e.g. R01 study) that will further inform aim 2 of the parent study. More specifically, it will help us understand whether the gut microbiome and metabolome are potential mediators between the observed relationship between high alcohol intake and adverse TB treatment outcomes. In summary, this study will supplement the goals of the parent study while adding valuable new avenues for assessments on potential modifiable mediators.