Point-of-purchase (POP) information at food stores could help promote healthy dietary habits. However, it has been difficult to evaluate the effects of such intervention on customers’ behavior. We objectively evaluated the usefulness of POP health information for vegetables in the modification of customers’ purchasing behavior by using the database of a point-of-sales (POS) system.

Two supermarket stores belonging to the same chain were assigned as the intervention store (store I) and control store (store C). POP health information for vegetables was presented in store I for 60 days. The percent increase in daily sales of vegetables over the sales on the same date of the previous year was compared between the stores by using the database of the POS system, adjusting for the change in monthly visitors from the previous year (adjusted ∆sales).

The adjusted ∆sales significantly increased during the intervention period (Spearman’s ρ = 0.258, P for trend = 0.006) at store I but did not increase at store C ( ρ = −0.037, P for trend = 0.728). The growth of the mean adjusted ∆sales of total vegetables from 30 days before the intervention period through the latter half of the intervention period was estimated to be greater at store I than at store C by 18.7 percentage points (95% confidence interval 1.6–35.9).

Health-related POP information for vegetables in supermarkets can encourage customers to purchase and, probably, consume vegetables.