Oldenlandia diffusa, also known as Hedyotis diffusa, is a herb widely used in traditional Chinese medicine (TCM). Its use in the context of tuberculosis is primarily based on traditional practices rather than robust scientific evidence. Historically, Oldenlandia diffusa has been included in TCM formulations aimed at "clearing heat and toxins" and "cooling the blood," which are concepts in TCM sometimes applied to infectious diseases such as tuberculosis. However, these TCM indications are not directly equivalent to the biomedical understanding of tuberculosis as a mycobacterial infection.

A search of the scientific literature reveals limited studies investigating Oldenlandia diffusa specifically for the treatment of tuberculosis. While some in vitro studies have demonstrated general antimicrobial or immunomodulatory effects of the plant's extracts, there is no high-quality clinical evidence or controlled trials supporting its efficacy against Mycobacterium tuberculosis in humans. The herb is occasionally mentioned in ethnobotanical surveys and TCM texts as a supportive treatment, often as part of multi-herb formulas, but its specific anti-tubercular role is not well established.

In summary, the use of Oldenlandia diffusa for tuberculosis is justified primarily by traditional medical systems, with very limited scientific validation. Evidence rating: 1 (anecdotal/traditional use without clinical validation).