The incidence of TB after solid organ transplantation ranges from 0. 9% to 11. 8%, mainly in relation to the local TB epidemic, but is much higher than in the general population. The incidence of postoperative TB reported in the literature is predominantly in renal transplant patients and relatively rare in liver transplant patients, but recent reports have increased (1). A recent report (2) showed that the incidence of active TB after liver transplantation was 1.3%, with a mean time to onset of 8.5 months postoperatively, generally with preoperative risk factors for TB (positive TB skin test, abnormal X-rays, clinical history). Extrapulmonary TB was common (67%), with multi-organ involvement (27%). 35% of cases required discontinuation or conversion of anti-TB therapy due to hepatotoxicity. Short-term mortality was 31%, with an 18-fold increase in the incidence of active TB in liver transplant recipients and a 4-fold increase in mortality compared with the normal population. There was a clear correlation between mortality and time of onset, with a cut-off of 5 months, with 36% mortality before onset and 17% after. The main problem of TB after liver transplantation is the difficulty of drug selection. The hepatotoxicity of conventional first-line antituberculosis drugs and interactions with immunosuppressive drugs limit their use in patients after liver transplantation. Isoniazid has significant hepatotoxicity, with an incidence of about 10% to 20% in the general population, with an incidence of fulminant liver failure of about 0. 7% to 17. 4% (1) Rifampin, which increases isoniazid toxic metabolites. Pyrazinamide, which can lead to fulminant liver failure. The toxicity of the combination is significantly higher than that of the single agent. In liver transplant patients, these problems are accentuated by the higher sensitivity of the transplanted liver to antituberculosis drug toxicity. meyers et al. reported an 83% incidence of drug-related hepatitis and a 50% incidence of associated acute rejection in post-transplant TB patients treated with isoniazid and rifampicin. a guado et al. (3) reported that 100% of liver transplant patients receiving antituberculosis A guado et al. (3) reported that 100% of liver transplant patients treated with antituberculosis exhibited drug hepatotoxicity, with 60% of these patients having a more severe condition, 14% requiring complete discontinuation of antituberculosis therapy, and a 30% graft loss rate. Isoniazid and rifampin activate hepatic microsomal enzymes and increase hormone catabolism. Rifampin, which may also include isoniazid, activates hepatic P450 enzymes and increases the catabolism of cyclosporine, predisposing it to rejection. Clinically, drug-induced hepatitis is difficult to distinguish from acute rejection and often relies on liver puncture biopsy. If rifampicin is necessary, the dose of cyclosporine should be increased by 3-5 times and the dose of hormone should be increased by 1 times, while the cyclosporine concentration should be monitored daily until it reaches a stable level. If necessary, tacrolimus (FK506) can be considered instead of cyclosporine A. Ethambutol and ofloxacin are the second-line anti-tuberculosis drugs. Ethambutol is a bacteriostatic agent. Ofloxacin has bactericidal efficacy at standard doses. Neither is hepatotoxic and there are no interactions with immunosuppressive drugs. Therefore, they have an important role in the anti-tuberculosis treatment after liver transplantation. Isoniazid para-aminosalicylate is a synthesis of isoniazid and para-aminosalicylic acid. Its hepatotoxicity is significantly less than that of isoniazid, and its gastrointestinal irritation is also less than that of para-aminosalicylic acid, and it is well tolerated by patients. Diagnosis of active tuberculosis after liver transplantation. The diagnosis of post-transplantation TB is difficult, with a reported time from onset to diagnosis of 7-90 days. Due to the application of immunosuppressive drugs, the positive rate of tuberculin skin test is low, and only 37% of active TB cases are positive for TST (> 5mm) (1) The positive rate of other diagnostic methods, such as TB antibodies, antacid staining of relevant specimens, QFT-G test, and culture of TB bacilli is also low, and a significant proportion of cases rely on puncture biopsy to confirm the diagnosis (2) Some cases are effectively treated with experimental antituberculosis therapy to enable diagnosis. Therefore, if there are preoperative risk factors for TB (positive TB skin test, abnormal X-rays, clinical history) and if there is a possibility of active TB after surgery, anti-tuberculosis treatment should be applied early. Treatment of active TB after liver transplantation is based on the chemotherapy regimen recommended by Meyers et al. (1): start with a traditional triple or quadruple dosing regimen lasting about 2 months, and after 2 months change to ethambutol + ofloxacin for a specific duration, usually 9 months, depending on the patient’s outcome. (4) Adopted regimen after liver transplantation. Regimen 1: isoniazid para-aminosalicylate (Likef Tribulus) + ethambutol + levofloxacin; Regimen 2: isoniazid + rifampicin + pyrazinamide; Regimen 3: streptomycin + rifampicin; Regimen 4: isoniazid + rifapentine + streptomycin + ethambutol + moxifloxacin. Total duration of treatment: 9 to 18 months, with triple or quadruple dosing for 2 months, followed by the continuation of ethambutol and levofloxacin for 7 to 10 months. Prevention of tuberculosis after liver transplantation. The prophylaxis of tuberculosis after liver transplantation is a controversial issue. The use of isoniazid as a prophylactic agent is controversial, and most believe that it should be avoided even in countries with a high incidence of tuberculosis because of its potential hepatotoxicity. (1) Positive preoperative tuberculin test in patients < 35 years of age or with chest radiographs suggestive of old tuberculosis foci. (2) Patients with newly positive tuberculin test. (3) Patients with inactive but untreated tuberculosis.