Arachidonate-enriched triglyceride oil does not promote tumor development in a rat medium-term multi-organ carcinogenesis model

► This study investigated the tumor modifying potential of arachidonate-enriched triglyceride (ARA-oil) in F344 rats. ► A rat medium-term multi-organ carcinogenesis bioassay was used. ► ARA-oil did not exert promoting potential on tumor development in any organs/tissues examined. ► No-effect level on tumor promotion of ARA-oil was 5% in diet in both sexes.