Two novel sesquiterpenoids of the furanogermacrane type, deacetylzeylanine (9) and parvigemonol (10), have been isolated from the stems of Neolitsea parvigemma. The autoxidation of the known pseudoneolinderane (6) afforded two unreported sesquiterpenoid dilactones, pseudoneolinderane-A (11) and pseudoneolinderane-B (12). Some of the sesquiterpenes showed significant inhibitory effects on platelet aggregation. The biogenetic pathway and the structure-activity relationships of some sesquiterpenoids are also discussed.