This chapter examines the role of diarrhoea in relation to the infant mortality rate (IMR). An analysis of the 1,621 deaths ascribed to diarrhoea/enteritis in the years 1876-1930, revealed that although such deaths occurred in every month of the year, by far the highest proportion were in July, August and September. The investigation of the incidence of diarrhoea in Ipswich is carried further by investigating possible links between it, social class and income. Deaths from diarrhoea were, as others have found, closely linked to changes in temperature. The decline of deaths from diarrhoea had a significant impact on the age distribution of infant deaths. When individual proximate causes of death are considered, the contribution of diarrhoea/enteritis to total deaths amongst the upper classes had a similar profile to those of the lower classes, although at lower levels throughout.