The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for $60^{circ}C$ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content ($211{mu}g$/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ($IC_{50}$ = 42.86 (absolute methanol) and $36.91{mu}g/mL$ (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in $H_2O_2/Fe^{3+}$/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at $400{mu}g/mL$ was observed to be highest ($10.2%{pm}1.03$). Moreover, methanolic RERC inhibited ${alpha}$-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.