Methods and compositions for treating or preventing diarrhea are disclosed. The methods comprise administering to an individual a therapeutically effective amount of an LPA<SUB>2 </SUB>receptor agonist for treating or preventing diarrhea. Also disclosed is a method of inhibiting CFTR activation by administering at least one LPA<SUB>2 </SUB>receptor agonist in an amount effective to inhibit formation of a macromolecular complex between the LPA<SUB>2 </SUB>receptor, CFTR, and a Na<SUP>+</SUP>/H<SUP>+</SUP> exchange regulatory factor-2 (NHERF-2).