Picrorhiza kurroa, a medicinal herb used in Ayurveda, has a traditional reputation as a "liver tonic." However, its use for fatty liver disease (non-alcoholic fatty liver disease, NAFLD) is supported by some scientific evidence, though the quality and quantity of this evidence are limited. Preclinical studies (mostly in animal models) have shown that extracts of Picrorhiza kurroa may exert hepatoprotective effects, reducing markers of liver injury, lipid accumulation in the liver, and oxidative stress. The putative active constituents, such as picroside I and II, are thought to modulate inflammatory and antioxidant pathways relevant to fatty liver disease.

A small number of human clinical studies have been conducted. For example, a randomized controlled trial published in Indian Journal of Pharmacology (2012) showed that Picrorhiza kurroa extract improved liver function tests and reduced hepatic steatosis in patients with NAFLD over 12 weeks. However, these trials are generally small, often lack rigorous blinding or placebo controls, and may be subject to bias. No large-scale, high-quality randomized controlled trials have firmly established its efficacy or safety for fatty liver disease.

In summary, while there is a scientific rationale and some preliminary clinical evidence for the use of Picrorhiza kurroa in supporting liver health and possibly improving fatty liver disease, the evidence base is still modest and not definitive. More robust human trials are needed to confirm its effectiveness and safety in this context.