1 Conclusion Bystander effect plays an important role in the cytocidal activity of TK/GCV against tumor cells, and is quite relative to intercellular contact.

2 The formation of inclusion bodies is morphologic evidence of viral cytocidal infection.

3 Objective To study the role of bystander effect in the cytocidal activity of TK/GCV against tumor cells.

4 Preliminary results showed that hernandezine blocked cell-cycle transfer from G1 to S phase, and its cytocidal action might be cell cycle specific.

5 Juglone's inhibition action on S180 cell shows that the effect is cytocidal and concentration-dependent in nature.