Fifteen patients with evidence of acute poststreptococcal glomerulonephritis were asked about their contact with vapours of organic solvents. Six patients reported brief exposure shortly before the onset of glomerulonephritis, 4 fairly long exposure, and 5 none or insignificant. At the latest followup, 3 of 4 patients who were still exposed to such solvents had proteinuria and a low glomerular filtration rate (GFR), and 2 were hypertensive. Of the 11 patients who had never been or were no longer exposed, the GFR was insignificantly decreased in 2, none had proteinuria and none were hypertensive. Fifteen age-and sex-matched controls, who had been infected with group A beta-hemolytic streptococci, T type 12, had not been exposed, or the exposure was insignificant and not related to the streptococcal infection. Exposure to organic solvents or other nephrotoxic agents may be the condition which determines the outcome of an infection with nephritogenic streptococci.