Further study on the chemical constituents present in the fruit of Averrhoa carambola L. (Oxalidaceae), commonly called star fruit or carambola, led to the isolation of six new dihydrochalcone C-glycosides, carambolasides E∼J (1∼6). Their structures were determined by spectroscopic and chemical methods, including low temperature nuclear magnetic resonance (NMR). Compounds 1∼6 and two alkaline hydrolysates, 5a and 6a, exhibited more potent 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical cation (ABTSradical dot+) scavenging activity with IC50 values ranging from 4.52 to 2.54 μM than l-ascorbic acid (14.21 μM). However, they were inactive in scavenging 1,1-diphenyl-2-picrylhydrazyl radical (DPPHradical dot) and in ferric reducing antioxidant power (FRAP).