Pneumococcal peritonitis complicating CAPD--was the indwelling intrauterine device to blame? A 45-year-old woman on CAPD developed pneumococcal peritonitis. This is the second such case of Streptococcus pneumoniae peritonitis complicating CAPD. The role of an indwelling intrauterine device (IUD) in producing ascending infection into the peritoneum is discussed, especially in women with evidence of retrograde menstruation. A review of the literature concerning pneumococcal peritonitis associated with IUD is given. Possible contraception to women on CAPD is briefly mentioned. 