Phospholipase A2 (PLA2; EC 3.1.1.4) is an enzyme involved in the formation of fatty acids and lysophospholipids, playing a key role in several biological processes. In addition to its enzymatic function, snake venom PLA2s exhibits various pharmacological activities, including neurotoxicity, antibacterial activity, induction of inflammatory events and oedema.  Flavonoids, a group of naturally occurring polyphenolic compounds, induce a dose-dependent inhibition of  in vitro phospholipid hydrolysis in both secretory and cytossolic PLA2, in a process not clearly known (Fawzy, A. A. et al., 1998, Agents Actions  25:394-400). Snake venom as well as other secretory PLA2 can form dimers with a molecular weight of 27-30 kDa. It has been shown that PLA2 isolated from C. d. terrificus venom exhibit an allosteric behavior in presence of synthetic substrate (Toyama, M.H. et al., 2003, Toxicon 41:1033-1038.), with dimer formation being crucial for enzymatic and pharmacological activities. In addition, recent studies revealed that a treatment of a PLA2 isolated from C. d. cascavella venom with flavonoids resulted in a considerable decrease in the enzymatic and antibacterial activities, even though inflammatory and neurotoxic activities were not affected (Iglesias, C. V. et al., 2005, Toxicon 46:751-758). An investigation of the effects of flavonoids on the  C. d. cascavella tertiary and quaternary structures is presented in this work. Small-Angle X-ray Scattering (SAXS) low resolution data have been collected for native PLA2 and PLA2 after a treatment with different flavonoids. Preliminary data analysis indicated that (i) tertiary structure was not completely damaged, suggesting that the arrangement of inner secondary structure elements was not affected by flavonoids; (ii) dimer formation has been observed both for native and treated enzyme.