ABSTRACT. Browning of the lettuce stem butt is one of the main postharvest changes induced by wounding during harvest. The browning process of the harvested lettuce starts with yellowing, then becomes reddish brown, and finishes with an intense brown pigmentation (Tomás-Barberán et al., 1997). Castañer et al. (1996) reported promising results to prevent butt discoloration of iceberg lettuce with solutions of acetic acid (10 ml/L and 50 ml/L), and vinegar. The objective of this work was to evaluate alternative methods to prevent butt discoloration of butterhead and iceberg lettuce during postharvest handling. @International Society for Horticultural Science.