One hundred consecutive cases with renal stones less than 3 cm in size and normal renal function underwent ESWL from January to March 1994. Out of these, 50 were given Andrographis paniculata tablets (250 mg), 4 tablests tid, 25 were given cotrimoxazole 2 tablets bid and 25 received norfloxacin 200 mg bid, started immediately after ESWL and continued for 5 days. All tolerated the treatment well and none had complications. At one month follow-up, pre- and post-ESWL pyuria, hematuria and proteinuria among the Andrographis paniculata group were 84, 58, 72, 40, 52, 22 per cent; the cotrimoxazole group 88, 64, 84, 64, 56, 44 per cent and the norfloxacin group 92, 56, 72, 40 per cent and 56, 28 per cent respectively. The results showed that post ESWL pyuria and hematuria in patients receiving Andrographis peniculata were reduced to 0.69 and 0.55 time of pre ESWL value. We think that this herbal medicine is beneficial in the treatment of post ESWL urinary tract infection. Besides the herbal drug given to eighteen previously sulfa sensitized patients resulted in no allergic reaction.