OBJECTIVE To explore the effects of Polygala tenuifolia compatibility on toxicity， anti-inflammatory and analgesic efficacy of sand-ironing Strychnos nux-vomica （SS）. METHODS The preparation of SS single decoction， SS-P. tenuifolia core-removed （PC） （1∶2.5） or （1∶5） combined decoction， and SS-PC （1∶5） mixture were carried out to investigate their median lethal dose （LD50）. Using aspirin as positive control， the number of writhing movements， analgesic rate， pain latency， ear swelling degree and inflammation inhibition rate induced by the above-mentioned medicinal liquids in mice were compared. The contents of the active and toxic components， strychnine and brucine， in the above-mentioned medicinal liquids were also determined. RESULTS The LD50 values of SS single decoction， SS-PC （1∶2.5） combined decoction， SS-PC （1∶5） combined decoction and SS- PC （1∶5） mixture were 302.00， 614.47， 1 445.44 and 1 778.28 mg/kg， respectively. Compared with control group， the number of writhing movements and ear swelling degree in the mice of the above-mentioned medicinal liquid groups were reduced or decreased significantly （P＜0.05 or P＜0.01）； pain latency [at 90 and 120 minutes in the SS single decoction group， at 60 and 90 minutes in the SS-PC （1∶2.5） combined decoction group， and at 60，90， 120 minutes in the SS-PC （1∶5） combined decoction group and SS-PC （1∶5） mixture group] was significantly prolonged （P＜0.05 or P＜0.01）； analgesic rates of the respective medicinal liquids were 39.30%， 70.87%， 80.00% and 82.46%， and inflammation inhibition rates were 38.08%，TD 57.89%， 76.47% and 50.46%； analgesic and anti-inflammatory effects of combined decoction and mixture were generally better than those of the single decoction （P＜0.05 or P＜0.01）. In the above-mentioned four medicinal liquids， the total contents of strychnine were 0.71%， 0.42%， 0.47% and 0.64%， and the total contents of brucine were 0.88%， 0.63%， 0.57% and 0.88%， respectively. CONCLUSIONS The combination of P. tenuifolia can reduce the toxicity of SS and enhance its anti-inflammatory and analgesic effects. Moreover， there is a tendency for the toxicity-reducing and efficacy-enhancing effects to increase with the increasing dosage of P. tenuifolia. Additionally， the combined decoction of SS and P. tenuifolia can reduce the contents of the active and toxic components， strychnine and brucine， in SS.