Background: In many cultures, simple herbal infusions, thin gruels, or sweetened water (aguitas in Guatemalan parlance) are given to infants and toddlers. Formative research has shown that the use of aguitas in early child feeding is deeply embedded in Guatemalan culture. Objective: We examined the prevalence and timing of the introduction of aguitas during early life in a low-income population of metropolitan Quetzaltenango in relation to stunting in children. Design: Responses from 456 mothers of children aged 5-23 mo were analyzed by using logistic regression to explore relations between linear growth (stunting), diarrhea, and age at the first introduction of agu itas. Results: A total of 358 of 456 infants (79%) were agu ita users independent of sex or ethnicity. Of infants given agu itas, one-fourth of subjects were introduced to aguitas within the first 2.9 wk of age, and one-half of subjects were introduced to aguitas within the first 9 wk of age. Subjects introduced to aguitas before 2.9 wk of age were 1.8 times more likely to be stunted (95% CI: 1.1, 2.8; P = 0.03) irrespective of ethnicity. Children who had ever been given aguitas were twice as likely to have also had diarrhea (OR: 2.1; 95% CI: 1.3, 3.3) and more likely to have needed medical attention for diarrhea (OR: 2.1; 95% CI: 1.1, 4.2), but diarrheal experience was independent of stunting. Conclusion: Because of the early introduction of aguitas and the high prevalence of stunting in Guatemala, longitudinal studies are urgently needed to clarify the causal relations. This trial was registered at Nederlands Trialregister as NTR3273 for 5-mo-olds and Nederlands Trialregister as NTR3292 for infants >6 mo. © 2013 American Society for Nutrition.