Graphical display of combination index (CI) when pancreatic cancer cells (ASPC1) are treated with varying concentrations of bromelain (Br), N-acetylcysteine (NAC) and in combinations with various chemotherapeutic agents. Synergy is shown when Br and NAC are combined at certain concentrations (A, B). Figure 1 (C) shows synergistic combinations of gemcitabine with NAC, Br and NAC + Br. (D-F) indicates almost an absence of synergy when gemcitabine, 5-FU, Oxaliplatin and doxorubicin are combined with Br, NAC or Br + NAC (G). Cisplatin at 3.0 & 6.0 ug/ml also synergises with only Br (G). The dotted lines show a CI = 1.0 (additivity), CI<1.0 = synergy, CI>1.0 = sub-additivity.