This study aimed to evaluate the biological activities of two Allium species (Garlic and onion) as well as diallyl disulphide (DADS) and dipropyl disulphide (DPDS) as their representative bioactive compounds in a multi-assay experimental design. The genotoxic, antigenotoxic and lifespan effects of garlic, onion, DADS and DPDS were checked in Drosophila melanogaster and their cytotoxic, pro-apoptotic and DNA-clastogenic activities were analysed using HL60 tumoral cells. All compounds were non-genotoxic and antigenotoxic against H2O2-induced DNA damage with a positive dose-response effect and different inhibition percentages (the highest value: 95% for DADS) at all tested concentrations. Daily intake of Allium vegetables, DADS or DPDS had no positive effects on flies’ lifespan and healthspan. Garlic and DADS exerted the highest cytotoxic effects in a positive dose-dependent manner. Garlic and DADS exerted a DNA-internucleosomal fragmentation as an index of induced proapoptotic activity on HL60 cells. Allium vegetables and DADS were able to induce clastogenic strand breaks in the DNA of HL60 cells. This study showed the genomic safety of the assayed substances and their protective genetic effects against the hydrogen peroxide genotoxine. Long-term treatments during the whole life of Drosophila genetic model were beneficial only at low-median concentrations. The chemopreventive activity of garlic could be associated to its distinctive organosulphur DADS. We suggest that supplementary studies are needed to clarify the cell death pathway against garlic and DADS.