In our studies with the pathogenic bacterium Clostridium perfringens type A and its cytotoxic-enterotoxins (CTEs), we have obtained results that imply an involvement of this organism in the sudden infant death syndrome (SIDS). In fecal samples obtained from SIDS infants (n = 164) and non-SIDS infants (n = 57), C. perfringens type A was present in high numbers in >80% of SIDS and <2% of control non-SIDS cases respectively. Fecal samples from SIDS infants analyzed by ELISA for C. perfringens type A CTEs showed a very strong positive correlation with the presence of the organism. Histopathological examination of ileal tissue from SIDS infants showed remarkable similarity to tissue from animal models affected by C. perfringens type A CTEs, where the patterns of damage were positively correlated with the age of the animal. We propose that systemic distribution of the CTEs acts parasympathomimetically to trigger a biochemical cascade that alters cardiorespiratory control. Death may subsequently ensue in an immunologically vulnerable infant.