Boldine　is　a　potential　anti-inflammatory　agent　found　in　several　different　plants.　Published　bioanalytical　methods　using　HPLC　with　ultraviolet　and　fluorescent　detection　lacked　enough　sensitivity　and　required　tedious　sample　preparation　procedures.　Herein,　we　describe　the　development　of　a　novel　ultra-high　performance　LC　with　MS/MS　for　determination　of　boldine　in　plasma.　Boldine　in　plasma　was　recovered　by　liquid-liquid　extraction　using　1mL　of　methyl　tert-butyl　ether.　Chromatographic　separation　was　performed　on　a　C-18　column　at　45　degrees　C,　with　a　gradient　elution　consisting　of　acetonitrile　and　water　containing　0.1%　(v/v)　formic　acid　at　a　flow　rate　of　0.3mL/min.　The　detection　was　performed　on　an　electrospray　triple-quadrupole　MS/MS　by　positive　ion　multiple　reaction　monitoring　mode.　Good　linearity　(r(2)＞0.9926)　was　achieved　in　a　concentration　range　of　2.555-2555ng/mL　with　a　lower　limit　of　quantification　of　2.555ng/mL　for　boldine.　The　intra-　and　inter-day　precisions　of　the　assay　were　1.2-6.0　and　1.8-7.4%　relative　standard　deviation　with　an　accuracy　of　-6.0-8.0%　relative　error.　This　newly　developed　method　was　successfully　applied　to　a　single　low-dose　pharmacokinetic　study　in　rats　and　was　demonstrated　to　be　simpler　and　more　sensitive　than　the　published　methods,　allowing　boldine　quantification　in　reduced　plasma　volume.　Copyright　(c)　2014　John　Wiley　&　Sons,　Ltd.