蛇足石杉（学名：Huperzia serrata）为石杉科石杉属下的一个种。

Huperzia serrata (toothed clubmoss) (TCM = Qian Ceng Ta/Jin Bu Huan) is a plant known as a firmoss which contains the acetylcholinesterase inhibitor huperzine A. It is widely distributed over-the-counter as a nootropic and dietary supplement.

This species is native to India and southeast Asia.