Two new polyhydroxy polyacetylenes, herpecaudenes A and B (1 and 2), were isolated from the ethanol extract of fruits of Herpetospermum caudigerum, an important Tibetan medicine. The structures of them were elucidated on the basis of extensive spectroscopic methods including UV, IR, HRESIMS, 1H and 13C NMR, HMBC, HSQC, and 1H-1H COSY. Compound 2 showed significant inhibitory effects on NO production in LPS-activated RAW 264.7 macrophages with IC50 values of 7.05 ± 1.59 µM.