Interaction of number of days with diarrhea and complications on cost burden incurred for a single episode of diarrhea, in a sample of 551 Bolivian infants seeking care for acute diarrheal illness, 2007–2009. For children who present with no complications, each additional day with diarrhea prior to treatment contributes to an increasingly greater cost burden. For those children who present with at least one complication, each additional day contributes to a greater cost burden until 12 days, at which point additional days contribute to a lower cost burden. The gray squares represent the contribution of number of days with diarrhea to the log10 of cost burden for children presenting with no complication. The black diamonds represent the contribution of number of days with diarrhea to the log10 of cost burden for children presenting with at least one complication. (N = 291).