Fagonia indica, a very important anticancer plant, has been less explored for its in vitro potential. This is the first report on thidiazuron (TDZ)-mediated callogenesis and elicitation of commercially important phenolic compounds. Among the five different plant growth regulators tested, TDZ induced comparatively higher fresh biomass, 51.0 g/100 mL and 40.50 g/100 mL for stem and leaf explants, respectively, after 6 weeks of culture time. Maximum total phenolic content (202.8 mu g gallic acid equivalent [GAE]/mL for stem-derived callus and 161.3 mu g GAE/mL for leaf-derived callus) and total flavonoid content (191.03 mu g quercetin equivalent [QE]/mL for stem-derived callus and 164.83 mu g QE/mL for leaf-derived callus) were observed in the optimized callus cultures. The high-performance liquid chromatography (HPLC) data indicated higher amounts of commercially important anticancer secondary metabolites such as gallic acid (125.10 +/- 5.01 mu g/mL), myricetin (32.5 +/- 2.05 mu g/mL), caffeic acid (12.5 +/- 0.52 mu g/mL), catechin (9.4 +/- 1.2 mu g/mL), and apigenin (3.8 +/- 0.45 mu g/mL). Owing to the greater phenolic content, a better 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (69.45 % for stem explant and 63.68 % for leaf explant) was observed in optimized calluses. The unusually higher biomass and the enhanced amount of phenolic compounds as a result of lower amounts of TDZ highlight the importance of this multipotent hormone as elicitor in callus cultures of F. indica.