Three new lycopodium alkaloids, 11alpha-hydroxyphlegmariurine B (2), 7alpha-hydroxyphlegmariurine B (3) and 7alpha,11alpha-dihydroxyphlegmariurine B (4) along with a known compound, phlegmariurine B (1), were isolated from the herb Huperzia serrata. The structures of the above compounds were elucidated based on spectroscopic studies.