It is found that S-Allyl-L-cysteine could protect against amyloid-protein (A)-and tunicamycin-induced cell death in differentiated PC12 cells. Simultaneously applied S-Allyl-L-cysteine (1 μM) suppresses the cell death induced by Aβ 25-35 and Aβ 1-40 in a concentration-dependent manner, and neuronal integrity is almost completely retained. Simultaneously applied S-Allyl-L-cysteine significantly decreases the Aβ-induced level of ROS. The TEAC value of S-Allyl-L-cysteine is lower than that of oxidized GSH, and no antioxidant activity is observed. Intracellular GSH levels remains unaffected by treatment of neurons with S-Allyl-L-cysteine for 24 h. Furthermore, the increase in caspase-12 protein expression is suppressed by simultaneously adding 1 μM S-Allyl-L-cysteine . S-Allyl-L-cysteine up to a concentration 1.0 mM does not exhibit any cytotoxic impact on morphology of myoblast and myotubes in culture observed under bright field microscope. TNF treatment leads to a significant decrease in the intracellular CK activity while S-Allyl-L-cysteine pre-treatment to TNF treated myotubes decreases the release of CK in media. S-Allyl-L-cysteine pre-treatment decreases the level of active form of this enzyme in S-Allyl-L-cysteine+TNF group. Similar observations are recorded at mRNA level for caspase-3. These results illustrate that S-Allyl-L-cysteine regulates apoptotic signals via suppressing the transcription and thus protein expression of caspase-3.