Allicin is an organosulfur compound found in garlic, which is well known for their anticancer properties, however, its application was limited due to its instability towards light, heat, and alkaline conditions. In order to improve the bioavailability and stability of allicin, allicin was loaded into the garlic straw nanocellulose hydrogels and its physiochemical properties and toxicity towards normal hepatocyte cells (L02) and cancerous cells (HepG2) were evaluated. Initially, garlic straw was used as raw material to extract cellulose (GSC) and the garlic straw nanocellulose (GSNC) with a particle size of 168.0 ± 0.65 nm was prepared. Then, GSNC hydrogels were further prepared. The swelling rate of hydrogels in various medium was also determined. Finally, allicin was loaded into the hydrogels. The results showed that GSNC hydrogels had the porous structure, high pH sensitivity and the swelling rate in simulated intestinal fluid was 3054.24%. The drug loading capacity of allicin was 166.4 mg/g and the entrapment efficiency of allicin in GSNC hydrogel was 83.20%. The release rate of allicin-GSNC hydrogel was the highest in simulated intestinal fluid, and it could release allicin slowly. Moreover, the allicin-GNSC hydrogel were non-toxic towards L02 cells and had obvious toxicity towards HepG2 cells.